Method for transmitting broadcast signal and apparatus for transmitting broadcast signal

ABSTRACT

The present invention provides a method for transmitting a broadcast signal. The method for transmitting a broadcast signal according to the present invention may comprise the steps of: generating a plurality of items of signaling information for signaling broadcast data; generating a link layer packet using the plurality of items of signaling information; generating a broadcast signal using the link layer packet; and transmitting the broadcast signal.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the National Phase of PCT International ApplicationNo. PCT/KR2015/003338, filed on Apr. 3, 2015, which claims priorityunder 35 U.S.C. 119(e) to U.S. Provisional Application No. 61/975,010,filed on Apr. 4, 2014, all of which are hereby expressly incorporated byreference into the present application.

TECHNICAL FIELD

The present invention relates to a broadcast signal transmission method,a broadcast signal reception method, a broadcast signal transmissionapparatus, and a broadcast signal reception apparatus.

BACKGROUND ART

Recently, broadcast environments using an Internet protocol (IP) in adigital broadcast system have become popular. A hybrid broadcast systemfor providing a broadcast service in conjunction with a broadcastnetwork and an Internet network will be expected to be established as anext-generation broadcast system. Accordingly, methods for preservingand developing technologies of a digital broadcast system using atypical IP have been considered. However, it takes a significantly longtime to completely convert a conventional broadcast system using atypical MPEG-2 TS into an IP broadcast system in terms of industry orpolicy, and thus a broadcast system that simultaneously supports IP andMPEG-2 TS needs to be considered.

DETAILED DESCRIPTION OF THE INVENTION Technical Problems

Accordingly, an object of the present invention is to provide abroadcast signal transmission apparatus and a broadcast signal receptionapparatus capable of transmitting and receiving a broadcast signal for anext-generation broadcast service and methods for transmitting andreceiving a broadcast signal for a next-generation broadcast service.

Technical Solutions

The object of the present invention can be achieved by providing amethod for transmitting a broadcast signal. The method for transmittinga broadcast signal according to the present invention includesgenerating a plurality of signaling information for signaling broadcastdata; generating a link layer packet using the plurality of signalinginformation, wherein the link layer packet includes a link layer headerand a link layer payload, the link layer header includes a packet typefield, a packet configuration field, and a count field, the packet typefield indicates that information included in the link layer payload issignaling information, the packet configuration information indicateswhether the link layer payload includes a plurality of signalinginformation, the count field indicates the number of the plurality ofsignaling information included in the link layer payload, and theplurality of signaling information is concatenated and then included inthe link layer payload; generating a broadcast signal using the linklayer packet; and transmitting the broadcast signal.

The link layer header may further include a signaling class field, aninformation type field, and a signaling format field, the signalingclass field may indicate an object signaled by the signalinginformation, the information type field may include data about thesignaling information, and the signaling format field may indicate aformat of the signaling information.

The signaling format field may indicate that the plurality of signalinginformation included in the link layer payload is a plurality of sectiontables.

A length of the link layer header may be determined by a value of thesignaling format field, and a length of the link layer payload may bedetermined by values of section length fields of the section tables.

The section length fields of the section tables may be sequentiallylocated in the link layer payload, the section length fields may belocated at fixed positions from respective start points of the sectiontables, and each of the section length fields may indicate a length of acorresponding section table.

The signaling format field may indicate that the plurality of signalinginformation included in the link layer payload is a plurality ofdescriptors.

The link layer header may further include a payload length partincluding a plurality of payload length fields, and each of the payloadlength fields may indicate a length of each of the plurality ofsignaling information.

Whether the link layer header further includes the payload length partmay be determined by a value of the signaling format field.

The object of the present invention can be achieved by providing amethod for transmitting a broadcast signal. The method for transmittinga broadcast signal according to the present invention includesgenerating signaling information for signaling broadcast data;generating a link layer packet using the signaling information, whereinthe link layer packet includes a link layer header and a link layerpayload, the link layer payload includes one of segments segmented fromthe signaling information, the link layer header includes a packet typefield and a packet configuration field, the packet type field indicatesthat information included in the link layer payload is signalinginformation, and the packet configuration information indicates whetherthe link layer payload includes one of segments segmented from thesignaling information; generating a broadcast signal using the linklayer packet; and transmitting the broadcast signal.

When a segment included in the link layer payload is a first segmentamong the segmented segments, the link layer header may further includea signaling class field, an information type field, and a signalingformat field, the signaling class field may indicate an object signaledby the signaling information, the information type field may includedata about the signaling information, and the signaling format field mayindicate a format of the signaling information.

The object of the present invention can be achieved by providing anapparatus for transmitting a broadcast signal. The apparatus fortransmitting a broadcast signal according to the present inventionincludes a first module for generating a plurality of signalinginformation for signaling broadcast data; a second module for generatinga link layer packet using the plurality of signaling information,wherein the link layer packet includes a link layer header and a linklayer payload, the link layer header includes a packet type field, apacket configuration field, and a count field, the packet type fieldindicates that information included in the link layer payload issignaling information, the packet configuration information indicateswhether the link layer payload includes a plurality of signalinginformation, the count field indicates the number of the plurality ofsignaling information included in the link layer payload, and theplurality of signaling information is concatenated and then included inthe link layer payload; and a third module for generating a broadcastsignal using the link layer packet and transmitting the broadcastsignal.

The link layer header further may include a signaling class field, aninformation type field, and a signaling format field, the signalingclass field may indicate an object signaled by the signalinginformation, the information type field may include data about thesignaling information, and the signaling format field may indicate aformat of the signaling information.

The signaling format field may indicate that the plurality of signalinginformation included in the link layer payload is a plurality of sectiontables.

A length of the link layer header may be determined by a value of thesignaling format field, and a length of the link layer payload may bedetermined by values of section length fields of the section tables.

The section length fields of the section tables may be sequentiallylocated in the link layer payload, the section length fields may belocated at fixed positions from respective start points of the sectiontables, and each of the section length fields may indicate a length of acorresponding section table.

The signaling format field may indicate that the plurality of signalinginformation included in the link layer payload is a plurality ofdescriptors.

The link layer header may further include a payload length partincluding a plurality of payload length fields, and each of the payloadlength fields may indicate a length of each of the plurality ofsignaling information.

Whether the link layer header may further include the payload lengthpart is determined by a value of the signaling format field.

The object of the present invention can be achieved by providing anapparatus for transmitting a broadcast signal. The apparatus fortransmitting a broadcast signal according to the present inventionincludes a first module for generating signaling information forsignaling broadcast data; a second module for generating a link layerpacket using the signaling information, wherein the link layer packetincludes a link layer header and a link layer payload, the link layerpayload includes one of segments segmented from the signalinginformation, the link layer header includes a packet type field and apacket configuration field, the packet type field indicates thatinformation included in the link layer payload is signaling information,and the packet configuration information indicates whether the linklayer payload includes one of segments segmented from the signalinginformation; and a third module for generating a broadcast signal usingthe link layer packet and transmitting the broadcast signal.

When a segment included in the link layer payload is a first segmentamong the segmented segments, the link layer header further may includea signaling class field, an information type field, and a signalingformat field, the signaling class field may indicate an object signaledby the signaling information, the information type field may includedata about the signaling information, and the signaling format field mayindicate a format of the signaling information.

Advantageous Effects

The present invention can provide an effective broadcast signaltransmission method, an effective broadcast signal reception method, aneffective broadcast signal transmission apparatus, and an effectivebroadcast signal reception apparatus.

In addition, the present invention can enhance data transfer efficiencyand enhance robustness for transmitting and receiving a broadcastsignal.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a protocol stack for a hybrid-basednext-generation broadcast system according to an embodiment of thepresent invention.

FIG. 2 is a diagram illustrating an interface of a link layer accordingto an embodiment of the present invention.

FIG. 3 is a diagram illustrating a packet structure of a link layeraccording to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a packet type according to a packettype element according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a header structure of a link layer whenan IP packet is transmitted to a link layer, according to an embodimentof the present invention.

FIG. 6 is a diagram illustrating meaning of a value denoted by a C/Sfield and header configuration information according to an embodiment ofthe present invention.

FIG. 7 is a diagram illustrating meaning of a value denoted by a countfield according to an embodiment of the present invention.

FIG. 8 is a diagram illustrating meaning of a value denoted by aSeg_Len_ID field and an equation for calculating a segment lengthaccording to an embodiment of the present invention.

FIG. 9 is a diagram illustrating a procedure for encapsulating a normalpacket and an equation for calculating a length of a link layer packetaccording to an embodiment of the present invention.

FIG. 10 is a diagram illustrating a procedure for encapsulating aconcatenated packet and an equation for calculating a length of a linklayer packet according to an embodiment of the present invention.

FIG. 11 is a diagram illustrating a procedure for obtaining a length ofa concatenated packet including an IPv4 packet and an equation forcalculating an offset value at which a length field of an IP packet ispositioned according to an embodiment of the present invention.

FIG. 12 is a diagram illustrating a procedure for calculating a lengthof a concatenated packet including an IPv6 packet and an equation forcalculating an offset value at which a length field of an IP packet ispositioned, according to an embodiment of the present invention.

FIG. 13 is a diagram illustrating a procedure for encapsulating asegmented packet according to an embodiment of the present invention.

FIG. 14 is a diagram illustrating a procedure for segmenting an IPpacket and header information of a link layer packet according to anembodiment of the present invention.

FIG. 15 is a diagram illustrating a procedure for segmenting an IPpacket including cyclic redundancy check (CRC) according to anembodiment of the present invention.

FIG. 16 is a diagram illustrating a header structure of a link layerpacket when an MPEG-2 transport stream (TS) is input to a link layer,according to an embodiment of the present invention.

FIG. 17 is a diagram illustrating the number of MPEG-2 TS packetsincluded in a payload of a link layer packet according to a value of acount field, according to an embodiment of the present invention.

FIG. 18 is a diagram illustrating a header of an MPEG-2 TS packetaccording to an embodiment of the present invention.

FIG. 19 is a diagram illustrating a procedure for changing use of atransport EI field by a transmitter according to an embodiment of thepresent invention.

FIG. 20 is a diagram illustrating a procedure for encapsulating anMPEG-2 TS packet according to an embodiment of the present invention.

FIG. 21 is a diagram illustrating a procedure for encapsulating MPEG-2TS packets having the same PIDs, according to an embodiment of thepresent invention.

FIG. 22 is a diagram illustrating a common PID reduction procedure andan equation for obtaining a length of a link layer packet during thecommon PID reduction procedure, according to an embodiment of thepresent invention.

FIG. 23 is a diagram illustrating the number of concatenated MPEG-2 TSpackets according to a value of a count field and a length of a linklayer packet according to the number when common PID reduction isapplied, according to an embodiment of the present invention.

FIG. 24 is a diagram illustrating a method for encapsulating an MPEG-2TS packet including a null packet, according to an embodiment of thepresent invention.

FIG. 25 is a diagram illustrating a procedure for processing anindicator for counting deleted null packets and an equation forobtaining a length of a link layer packet during the procedure,according to an embodiment of the present invention.

FIG. 26 is a diagram illustrating a procedure for encapsulating anMPEG-2 TS packet including a null packet, according to anotherembodiment of the present invention.

FIG. 27 is a diagram illustrating a procedure for encapsulating MPEG-2TS packets including the same packet identifier (PID) in a streamincluding a null packet, according to an embodiment of the presentinvention.

FIG. 28 is a diagram illustrating an equation for obtaining a length ofa link layer packet while MPEG-2 TS packets including the same packetidentifier (PID) are encapsulated in a stream including a null packet,according to an embodiment of the present invention.

FIG. 29 is a diagram illustrating a configuration of a link layer packetfor signaling transmission, according to an embodiment of the presentinvention.

FIG. 30 is a diagram illustrating a configuration of a link layer packetfor transmission of a framed packet, according to an embodiment of thepresent invention.

FIG. 31 is a diagram illustrating syntax of a framed packet according toan embodiment of the present invention.

FIG. 32 is a diagram illustrating a receiver of a next-generationbroadcast system, according to an embodiment of the present invention.

FIG. 33 is a diagram illustrating normal format of a section tableaccording to an embodiment of the present invention.

FIG. 34 is a diagram illustrating a structure of a link layer packet fortransmission of signaling, according to an embodiment of the presentinvention.

FIG. 35 is a diagram illustrating meaning of a value denoted by asignaling type field and contents of a fixed header and extended headersubsequent to the signaling type field, according to an embodiment ofthe present invention.

FIG. 36 is a diagram illustrating the number of descriptors included ina payload of a link layer packet according to a concatenation countvalue, according to an embodiment of the present invention.

FIG. 37 is a diagram illustrating a procedure for encapsulating asection table in a payload when signaling information input to a payloadof a link layer packet is a section table, according to an embodiment ofthe present invention.

FIG. 38 is a diagram illustrating syntax of a network information table(NIT) according to an embodiment of the present invention.

FIG. 39 is a diagram illustrating syntax of a delivery system descriptorincluded in a network information table (NIT), according to anembodiment of the present invention.

FIG. 40 is a diagram illustrating syntax of a fast information table(FIT) according to an embodiment of the present invention.

FIG. 41 is a diagram illustrating a procedure for encapsulating adescriptor in a payload when signaling information input to a payload ofa link layer packet is a descriptor, according to an embodiment of thepresent invention.

FIG. 42 is a diagram illustrating syntax of a fast informationdescriptor according to an embodiment of the present invention.

FIG. 43 is a diagram illustrating a delivery system descriptor accordingto an embodiment of the present invention.

FIG. 44 is a diagram illustrating a procedure for encapsulating oneGSE-LLC item in a payload of one link layer packet when signalinginformation input to a payload of a link layer packet is a GSE-LLC typeused in the DVB-GSE standard, according to an embodiment of the presentinvention.

FIG. 45 is a diagram illustrating a procedure for encapsulating oneGSE-LLC data item in payloads of a plurality of link layer packets whensignaling information input to a payload of a link layer packet is aGSE-LLC type used in the DVB-GSE standard, according to an embodiment ofthe present invention.

FIG. 46 is a diagram illustrating a method for transmitting signalinginformation according to an embodiment of the present invention.

FIG. 47 is a diagram illustrating a header of a link layer packet forrobust header compression (RoHC) transmission according to an embodimentof the present invention.

FIG. 48 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet according to Embodiment #1 of thepresent invention.

FIG. 49 is a diagram of a method for transmitting an RoHC packet througha link layer packet according to Embodiment #2 of the present invention.

FIG. 50 is a diagram illustrating a method for transmitting an RoHCpacket of a link layer packet according to Embodiment #3 of the presentinvention.

FIG. 51 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet according to Embodiment #4 of thepresent invention.

FIG. 52 is a diagram illustrating a header of a link layer packet forRoHC transmission when MTU is 1500, according to an embodiment of thepresent invention.

FIG. 53 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #1 of the present invention.

FIG. 54 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #2 of the present invention.

FIG. 55 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #3 of the present invention.

FIG. 56 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #4 of the present invention.

FIG. 57 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #5 of the present invention.

FIG. 58 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #6 of the present invention.

FIG. 59 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #7 of the present invention.

FIG. 60 is a diagram illustrating a configuration of a header of a linklayer packet when an IP packet is transmitted to a link layer, accordingto another embodiment of the present invention.

FIG. 61 is a diagram illustrating information indicated by each field ina header of a link layer packet when an IP packet is transmitted to alink layer, according to another embodiment of the present invention.

FIG. 62 is a diagram illustrating the case in which one IP packet isincluded in a link layer payload with respect to a header of a linklayer packet when an IP packet is transmitted to a link layer, accordingto another embodiment of the present invention.

FIG. 63 is a diagram illustrating the case in which a plurality of IPpackets is concatenated and included in a link layer payload withrespect to a header of a link layer packet when an IP packet istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 64 is a diagram illustrating the case in which one IP packet issegmented and included in a link layer payload with respect to a headerof a link layer packet when an IP packet is transmitted to a link layer,according to another embodiment of the present invention.

FIG. 65 is a diagram illustrating link layer packets having segmentedsegments with respect to a header of a link layer packet when an IPpacket is transmitted to a link layer, according to another embodimentof the present invention.

FIG. 66 is a diagram illustrating a method for using CRC encoding withrespect to a header of a link layer packet when an IP packet istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 67 is a diagram illustrating a configuration of a link layer packetwhen signaling information is transmitted to a link layer according toanother embodiment of the present invention.

FIG. 68 is a diagram illustrating meaning of values indicated by fieldswith respect to a configuration of a link layer packet when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

FIG. 69 is a diagram illustrating a configuration of a link layer packetwhen signaling information is one section table with respect to theconfiguration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 70 is a diagram illustrating a configuration of a link layer packetwhen signaling information is one descriptor with respect to theconfiguration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 71 is a diagram illustrating a configuration of a link layer packetwhen signaling information is a plurality of descriptors with respect tothe configuration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 72 is a diagram illustrating a configuration of a link layer packetwhen signaling information is a plurality of section tables with respectto the configuration of the link layer packet when signaling informationis transmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 73 is a diagram illustrating a configuration of a link layer packetwhen signaling information does not have a separate length value withrespect to the configuration of the link layer packet when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

FIG. 74 is a diagram illustrating a configuration of a link layer packetwhen one signaling information item is segmented into a plurality ofsegments with respect to the configuration of the link layer packet whensignaling information is transmitted to a link layer, according toanother embodiment of the present invention.

FIG. 75 is a diagram illustrating a method for transmitting a broadcastsignal according to an embodiment of the present invention.

FIG. 76 is a diagram illustrating an apparatus for transmitting abroadcast signal according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Reference will now be made in detail to the embodiments, examples ofwhich are illustrated in the accompanying drawings. However, theembodiments should not be construed as limited to the exemplaryembodiments set forth herein.

Although most terms of elements in the present disclosure have beenselected from general ones widely used in the art taking intoconsideration functions thereof in the present disclosure, the terms maybe changed depending on the intention or custom of those skilled in theart or the introduction of new technology. Some terms have beenarbitrarily selected by the applicant and their meanings are explainedin the following description as needed. Thus, the terms used in thepresent disclosure should be construed based on the overall content ofthe present disclosure together with the actual meanings of the termsrather than their simple names or meanings.

In the specification, the term ‘signaling’ may indicatetransmission/reception of service information (SI) that is provided in abroadcast system, an Internet broadcast system, and/or abroadcast/Internet convergence system. The SI may include broadcastservice information (e.g., ATSC-SI and/or DVB-SI) provided in eachcurrently existing broadcast system.

In the specification, the term ‘broadcast signal’ is defined asincluding signals and/or data provided in bidirectional broadcastingsuch as Internet broadcasting, broadband broadcasting, communicationbroadcasting, data broadcasting, and/or video on demand (VOD) as well asterrestrial broadcasting, cable broadcasting, satellite broadcasting,and/or mobile broadcasting.

In the specification, the term ‘physical layer pipe (PLP)’ refers to apredetermined unit for transmitting data belonging to a physical layer.Accordingly, in the specification, the term ‘PLP’ may be replaced withthe term ‘data unit’ or ‘data pipe’.

One important application to be used in a digital broadcast (DTV)service is a hybrid broadcast service based on connection between abroadcast network and an Internet network. The hybrid broadcast servicemay transmit enhancement data associated with broadcast audio/video(A/V) content transmitted through a terrestrial broadcasting network orsome of the A/V content in realtime through the Internet so as to allowusers to experience various content.

The present invention proposes a method for encapsulating an IP packetand an MPEG-2 TS packet and a packet to be used in other broadcastsystems so as to be transmitted to a physical layer in a next-generationdigital broadcast system. In addition, the present invention alsoproposes a method for transmitting layer-2 signaling in the same headerformat.

The description below may be embodied in a device. For example, thedescription below may be performed by, for example, a signalingprocessor, a protocol processor, a processor, and/or a packet generator.

The present invention provides a method and apparatus for transmittingand receiving a broadcast signal for a next-generation broadcastservice. A next-generation broadcast service according to an embodimentof the present invention is interpreted as including a terrestrialbroadcasting service, a mobile broadcasting service, an ultra highdefinition television (UHDTV) service, and the like. According to anembodiment of the present invention, a broadcast signal for theaforementioned next-generation broadcast service may be process abroadcast signal using a non-multiple input multiple output (non-MIMO)scheme or a MIMO scheme. A non-MIMO scheme according to an embodiment ofthe present invention may include a multi input single output (MISO)method, a single input single output (SISO) method, and the like.

While MISO or MIMO uses two antennas as an example in the following forconvenience of description, the present invention is applicable tosystems using two or more antennas.

FIG. 1 is a diagram illustrating a protocol stack for a hybrid-basednext-generation broadcast system according to an embodiment of thepresent invention.

The present invention proposes a structure of a data link(encapsulation) portion illustrated in FIG. 1 and proposes a method fortransferring an MPEG-2 transport stream (TS) and/or an Internet protocol(IP) packet transmitted from an upper layer to a physical layer. Inaddition, the present invention proposes a method for transmittingsignaling required for an operation of a physical layer and establishesa base for transmitting a new packet type to a physical layer when ahigher layer considers the new packet type for future use.

A corresponding protocol layer may also be referred to as various termssuch as a data link layer, an encapsulation layer, layer 2, and thelike. In the present invention, the protocol layer is referred to as alink layer. In actual application to the present invention, the protocollayer may be substituted with the term ‘link layer’ or a correspondinglayer may also be referred to by a new term.

A broadcast system according to the present invention may correspond toa hybrid broadcast system obtained by combining an IP centric broadcastnetwork and a broadband network.

The broadcast system according to the present invention may be designedto maintain compatibility with a conventional MPEG-2-based broadcastsystem.

The broadcast system according to the present invention may correspondto a hybrid broadcast system based on combination of an IP centricbroadcast network, a broadband network, and/or a mobile communicationnetwork or a cellular network.

Referring to FIG. 1, a physical layer may use a physical protocolemployed by a broadcast system such as an ATSC system and/or a DVBsystem.

An encapsulation layer may acquire an IP datagram from informationacquired from the physical layer or convert the acquired IP datagraminto a specific frame (e.g., RS frame, general stream encapsulation(GSE)-Lite, GSE, or signal frame). Here, the frame may include a setsuch as a set of IP datagrams.

A fast access channel (FAC) may include information (e.g., mappinginformation between a service ID and a frame) for access to a serviceand/or content.

The broadcast system according to the present invention may useprotocols such as an Internet protocol (IP), a user datagram protocol(UDP), a transmission control protocol (TCP), asynchronous layeredcoding/layered coding transport (ALC/LCT), a rate control protocol/RTPcontrol protocol (RCP/RTCP), a hypertext transfer protocol (HTTP), andfile delivery over unidirectional transport (FLUTE). A stack betweenthese protocols may be understood with reference to the structureillustrated in FIG. 1.

In the broadcast system according to the present invention, data may betransmitted in the form of ISO base media file format (ISOBMFF).Electrical service guide (ESG), non real time (NRT), A/V, and/or generaldata may be transmitted in the form of ISOBMFF.

Transmission of data over a broadcast network may include transmissionof linear content and/or transmission of non-linear content.

Transmission of RTP/RTCP-based A/V, and data (closed captioning, anemergency alert message, etc.) may correspond to transmission of linearcontent.

An RTP payload may be encapsulated for transmission in the form of anRTP/AV stream and/or an ISO based media file format including a networkabstraction layer (NAL). Transmission of the RTP payload may correspondto transmission of linear content. Transmission in the form ofencapsulation of ISO based media file format may include an MPEG DASHmedia segment for A/V, etc.

Transmission of FLUTE-ESG, transmission of non-timed data, andtransmission of NRT content may correspond to transmission of non-linearcontent. The FLUTE-ESG, the non-timed data, and the NRT content may beencapsulated for transmission in the form of a MIME type file and/or ISObased media file format. Transmission after encapsulation into an ISObased media file format may include an MPEG DASH media segment for A/V,etc.

Transmission over a broadcast network may be separately considered astransmission of content and transmission of signaling data.

Transmission of content may include transmission of linear content (A/Vand data (closed captioning, emergency alert message, etc.),transmission of non-linear content (ESG, non-timed data, etc.), andtransmission of an MPEG DASH-based media segment (AN and data).

Transmission of signaling data may include transmission of datacontaining a signaling table (which includes MPD of MPEG DASH)transmitted on a broadcast network.

The broadcast system according to the present invention may supportsynchronization between linear/non-linear contents transmitted over abroadcast network or synchronization between content transmitted througha broadcast network and content transmitted through a broadband network.For example, when one UD content item is segmented and simultaneouslytransmitted over the broadcast network and the broadband, a receiver mayadjust a timeline dependent upon a transmission protocol and synchronizecontent of the broadcast network and content of the broadband network toreconfigure one UD content item.

An application layer of the broadcast system according to the presentinvention may achieve technological characteristics of interactivity,personalization, second screen, and automatic content recognition (ACR).These characteristics may be important to extension to ATSC3.0 fromATSC2.0 as North America broadcast standard. For example, forcharacteristics of interactivity, HTML5 may be used.

In a presentation layer of the broadcast system according to the presentinvention, HTML and/or HTML5 may be used to identify a spatial andtemporal relationship between components or between interactiveapplications.

A broadcast system according to another embodiment of the presentinvention may be implemented by addition or modification of theaforementioned broadcast system and thus the description of individualcomponents may be substituted with the above description of theaforementioned broadcast system.

A broadcast system according to another embodiment of the presentinvention may include a system structure that maintains compatibilitywith an MPEG-2 system. For example, linear/non-linear contenttransmitted by a conventional MPEG-2 system may be supported to bereceived and operated in an ATSC 3.0 system or processing of A/V anddata may be flexibly adjusted according to data received in the ATSC 3.0system, that is, whether the data is an MPEG-2 TS or an IP datagram.

An encapsulation layer of the broadcast system according to anotherembodiment of the present invention may convert information/dataacquired from a physical layer into an MPEG-2 TS or an IP datagram orconvert the information/data into a specific frame (e.g., RS Frame,GSE-Lite, GSE, or signal frame) using the IP datagram.

The broadcast system according to another embodiment of the presentinvention may include signaling information that can be flexiblyacquired according to whether data received in the ATSC 3.0 system isMPEG-2 TS or IP datagram in order to acquire services/content through abroadcast network. That is, the broadcast system may acquire signalinginformation based on MPEG-2 TS or acquire signaling information fromdata according to a UDP protocol.

The broadcast system according to the present invention may supportsynchronization between broadcast-based linear/non-linear contentencapsulated in the form of MPEG-2 TS and/or IP datagram. In addition,the broadcast system may support synchronization between contentfragments transmitted through the broadcast network and the broadbandnetwork. For example, when one UD content item is segmented and issimultaneously transmitted over the broadcast network and the broadbandnetwork, a receiver may adjust a timeline dependent upon a transmissionprotocol and synchronize content of the broadcast network and content ofthe broadband network to reconfigure one UD content item.

FIG. 2 is a diagram illustrating an interface of a link layer accordingto an embodiment of the present invention.

A transmitter may consider the case in which an IP packet and/or anMPEG-2 TS packet that are mainly used in digital broadcasting are usedas input signals. The transmitter may also support a packet structure ofa new protocol capable of being used in a next-generation broadcastingsystem. Data and singling that are encapsulated in a link layer may betransmitted to a physical layer. The transmitter may perform processingappropriate for a protocol of a physical layer supported by a broadcastsystem on the transmitted data (including signaling data) to transmit asignal including the corresponding data.

A receiver may recover data and signaling received from the physicallayer in the form of data that can be processed in a higher layer. Thereceiver may differentiate whether a packet received from the physicallayer is signaling (or signaling data) or data (or content data) byreading a header of a packet or via other methods to be described later.

Signaling (i.e., signaling data) received from the link layer of thetransmitter may include signaling that is received from an upper layerand needs to be transmitted to an upper layer of the receiver, signalingthat is generated from the link layer and provides information regardingdata processing in the link layer of the receiver, and/or signaling thatis generated from the upper layer or the link layer but is transmittedfor rapid detection of specific data (e.g., service, content, and/orsignaling data) in a physical layer.

FIG. 3 is a diagram illustrating a packet structure of a link layeraccording to an embodiment of the present invention.

According to an embodiment of the present invention, the packet of thelink layer may include a fixed header, an extended header, and/or apayload.

The fixed header may be a header with a fixed size. For example, thefixed header may have a size of 1 byte. The extended header may be aheader with a changeable size. The payload containing data transmittedby a higher layer may be positioned behind the fixed header and theextended header.

The fixed header may include a packet type element and/or an indicatorpart element.

The packet type element may have a size of 3 bits. The packet typeelement may identify a packet type of a higher layer (a higher layer ofa link layer). A packet type identified according to a value of a packettype element will be described later.

The indicator part element may include a method for configuring apayload and/or information for configuring an extended header. Theconfiguration method and/or the configuration information indicated bythe indicator part element may be changed according to a packet type.

FIG. 4 is a diagram illustrating a packet type according to a packettype element according to an embodiment of the present invention.

For example, when a value of the packet type element is ‘000’, thisindicates that a packet transmitted to a link layer from a higher layeris an IP version 4 (IPv4) packet.

If a value of a packet type element is ‘001’, this indicates that apacket transmitted to a link layer form a higher layer is an IP version6 (IPv6) packet.

If a value of a packet type element is ‘010’, this indicates that apacket transmitted to a link layer from a higher layer is a compressedIP packet.

If a value of a packet type element is ‘011’, this indicates that apacket transmitted to a link layer from a higher layer is an MPEG-2 TSpacket.

If a value of a packet type element is ‘101’, this indicates that apacket transmitted to a link layer from a higher layer is a packetizedstream packet. For example, the packetized stream may correspond to anMPEG media transport packet.

If a value of a packet type element is ‘110’, this indicates that apacket transmitted to a link layer from a higher layer is a packet fortransmitting signaling (signaling data).

If a value of a packet type element is ‘111’, this indicates that apacket transmitted to a link layer from a higher layer is a framedpacket type.

FIG. 5 is a diagram illustrating a header structure of a link layer whenan IP packet is transmitted to a link layer, according to an embodimentof the present invention.

When the IP packet is input to a link layer, a value of a packet typeelement may be 000B (3 bits of 000) or 001B (3 bits of 001).

Referring to a packet header of the link layer when the IP packet isinput, an indicator part element subsequent to the packet type elementmay include a concatenation/segmentation (C/S) field and/or anadditional field of 3 bits (hereinafter, referred to as ‘additionalfield’).

With regard to a link layer packet, an additional field of a fixedheader and information of an extended header may be determined accordingto the C/S field of 2 bits subsequent to the packet type element.

The C/S field may indicate the form in which an input IP packet isprocessed and include information about the length of an extended headeraccording thereto.

According to an embodiment of the present invention, the case in which avalue of the C/S field is 00B (2 bits of 00) indicates that a payload ofthe link layer packet includes a normal packet. The normal packet mayrefer to the case in which an input IP packet is a payload of the linklayer packet without change. In this case, the additional field of thefixed header part may be reserved for future use. In this case, theextended header may not be used.

If a value of the C/S field is 01B (2 bits of 01), this indicates that apayload of the link layer packet includes a concatenated packet. Theconcatenated packet may include one or more IP packets. That is, one ormore IP packets may be included in the payload of the link layer packet.In this case, the extended header may not be used, and an additionalfield subsequent to the C/S field may be used as a count field. Adetailed description of the count field will be given later.

If a value of the C/S field is 10B (2 bits of 10), this indicates that apayload includes a segmented packet. The segmented packet may be apacket including one segmented by dividing one IP packet into severalsegments. That is, the payload of the link layer packet may include anyone of a plurality of segments included in an IP packet. An additionalfield subsequent to the C/S field may be used as a segment ID. Thesegment ID may be information for uniquely identifying a segment. Thesegment ID may be an ID assigned when an IP packet is segmented and mayindicate that segments that are transmitted for future use arecomponents of the same IP packet when the segments are combined. Thesegment ID may have a size of 3 bits and may simultaneously supportsegmentation of 8 IP packets. For example, segments segmented from oneIP packet may have the same segment ID. In this case, the extendedheader may have a length of 1 byte. In this case, the extended headermay include a segment sequence number (Seg_SN) field and a segmentsequence number field, and/or a segment length (Seg_Len_ID) field.

The segment sequence number (Seg_SN) field may have a length of 4 bitsand indicate a sequence number of a corresponding segment in an IPpacket. When the IP packet of the Seg_SN field is segmented, the Seg_SNfield may be a field used to check a sequence of each segment.Accordingly, link layer packets including a payload segmented from oneIP packet may have the same segment ID (Seg_ID) but have differentvalues of a Seg_SN field. The Seg_SN field may have a size of 4 bits,and in this case, one IP packet can be segmented into up to 16 segments.In order to segment an IP packet into more segments, a size of a Seg_SNfield may be extended and may indicate a sequence and/or number of asegment.

The segment length ID (Seg_Len_ID) field may have a length of 4 bits andmay be an ID for identifying a length of a segment. An actual length ofa segment according to a value of the Seg_Len_ID field may be identifiedaccording to a table to be described later. When an actual length valueof a segment instead of the Seg_Len_ID field is signaled, the Seg_Len_IDfield of 4 bits may be extended to a segment length field of 12 bits,and in this case, an extended header of 2 bits may be included in a linklayer packet.

If a value of the C/S field is 11B (2 bits of 11), this indicates that apayload includes a segmented packet as in the case in which a value ofthe C/S field is 10B. However, the C/S field of 11B may also indicatethat a segment (of a last sequence) positioned last among segmentssegmented from one IP packet is included in a payload. A receiver mayidentify a link layer packet for transmitting a last segment andrecognize a segment included in a payload of a corresponding packet as alast segment of an IP packet using a value of the C/S field duringreconfiguration of one IP packet by collecting segments. An additionalfield subsequent to the C/S field may be used as a segment ID. In thiscase, the extended header may have a length of 2 bytes. The extendedheader may include a segment sequence number (Seg_SN) field and/or alast segment length (L_Seg_Len) field.

The last segment length (L_Seg_Len) field may indicate an actual lengthof a last segment. When an IP packet is segmented into the same sizefrom a front part using the Seg_Len_ID field, a last segment may have adifferent size from other previous segments. Accordingly, a length of asegment may be directly indicated using the L_Seg_Len field. The lengthmay be different according to an allocated bit number of the L_Seg_Lenfield. However, when allocating the number of bits according to anembodiment of the present invention, the L_Seg_Len field may indicatethat a length of a last segment is 1 to 4095 bytes.

That is, when one IP packet is segmented into a plurality of segments,the IP packet may be segmented into segments with a predeterminedlength. However, a length of the last segment may be changed accordingto the length of the IP packet. Accordingly, a length of a last segmentneeds to be separately signaled. A description of a field with the samename is substituted with the above description.

FIG. 6 is a diagram illustrating meaning of a value denoted by a C/Sfield and header configuration information according to an embodiment ofthe present invention.

If a value of the C/S field is 00, this indicates that a normal packetis included in a payload of a link layer packet and an additional fieldis reserved. Meanwhile, an extended header may not be included in thelink layer packet. In this case, a total length of a header of the linklayer packet may be 1 byte.

If a value of the C/S field is 01, a concatenated packet may be includedin a payload of a link layer packet and the additional field may be usedas a count field. The count field will be described later. The extendedheader may not be included in a link layer packet. In this case, a totallength of a header of the link layer packet may be 1 byte.

When a value of the C/S field is 10, a segmented packet may be includedin a payload of a link layer packet and the additional field may be usedas a segment ID. The extended header may be included in the link layerpacket. The extended header may include a Seg_SN field and/or aSeg_Len_ID field. A description of the Seg_SN field or the Seg_Len_IDfield may be substituted with the above or following description. Atotal length of the header of the link layer packet may be 2 bytes.

When a value of the C/S field is 11, a segmented packet (a packetincluding a last segment) may be included in a payload of a link layerpacket and an additional field may be used as a segment ID. The extendedheader may be included in a link layer packet. The extended header mayinclude a Seg_SN field and/or an L_Seg_Len field. A description of theSeg_SN field or the L_Seg_Len field is substituted with the above orfollowing description. A total length of a header of a link layer packetmay be 3 bytes.

FIG. 7 is a diagram illustrating meaning of a value denoted by a countfield according to an embodiment of the present invention.

A count field may be used when a payload of a link layer packet includesa concatenated packet. The count field may indicate the number of IPpackets included in one payload. A value of the count field may indicatethe number of IP packets that are concatenated without change. However,since zero or one concatenation is meaningless, the count field mayindicate that an IP packet with the number obtained by adding 2 to thevalue of the count field is included in a payload. According to anembodiment of the present invention, 3 bits are allocated to the countfield, and thus this may indicate that a maximum of 9 IP packets areincluded in a payload of one link layer packet. When more IP packetsneed to be included in one payload, a length of the count field may beextended or 9 or more IP packets may be further signaled in the extendedheader.

FIG. 8 is a diagram illustrating meaning of a value denoted by aSeg_Len_ID field and an equation for calculating a segment lengthaccording to an embodiment of the present invention.

The Seg_Len_ID field may be used to represent a length of a segmentexcept for a last segment among a plurality of segments. In order toreduce overhead of a header that is required to represent the length ofa segment, the size of a segment may be limited to 16.

A length of a segment may be determined according to an input size of apacket determined according to a code rate of forward error correction(FEC) processed by a physical layer and may be determined as each valueof the Seg_Len_ID field. For example, with respect to each value of theSeg_Len_ID field, a length of a segment may be predetermined. In thiscase, information about a length of a segment according to each value ofthe Seg_Len_ID field may be generated by a transmitter and transmittedto a receiver, and the receiver may store the information. A length of asegment set according to each value of the Seg_Len_ID field may bechanged, and in this case, the transmitter may generate new informationabout the length of the segment and transmit the information to thereceiver, and the receiver may update stored formation based on theinformation.

When processing of a physical layer is performed irrespective of thelength of the segment, the length of the segment may be acquired asshown in the illustrated equation.

Here, a length unit (Len_Unit) may be a basic unit indicating a segmentlength and min_Len may be a minimum value of a segment length. Len_Unitand min_Len need to be the same in the transmitter and the receiver, andit may be effective that Len_Unit and min_Len are not changed afterbeing changed once. The values may be determined in consideration ofprocessing capability of FEC of a physical layer in an initializationprocedure of a system. For example, as illustrated, the values mayindicate a length of a segment that is represented according to thevalue of the Seg_Len_ID field, and in this case, a value of Len_Unit maybe 256 and a value of min_Len may be 512.

FIG. 9 is a diagram illustrating a procedure for encapsulating a normalpacket and an equation for calculating a length of a link layer packetaccording to an embodiment of the present invention.

As described above, when an input IP packet is not concatenated orsegmented within a processing range of a physical layer as describedabove, the input IP packet may be encapsulated as a normal packet. Thefollowing description may be applied to an IP packet of IPv4 or IPv6 inthe same way. One IP packet may be a payload of a link layer packetwithout change, and a value of a packet type element may be 000B (IPv4)or 001B (IPv6), and a value of the C/S field may be 00B (normal packet).The remaining 3 bits of a fixed header may be set as a reserved fieldfor other future use.

The length of the link layer packet may be identified as follows. Theheader of the IP packet may include a field indicating a length of an IPpacket. A field indicating a length is positioned at the same position,and thus the receiver may check a field at a position spaced apart froman initial point (a start point) of a link layer packet by apredetermined offset so as to recognize the length of a payload of alink layer packet. The receiver may read a length field with a length of2 bytes from a position spaced apart from a start point of a payload by2 bytes in the case of IPv4 and from a position spaced apart from astart point of a payload by 4 bytes in the case of IPv6.

Referring to the illustrated equation, when a value of a length field ofIPv4 is LIPv4, LIPv4 indicates a total length of IPv4, and thus anentire length of the link layer packet may be obtained by adding aheader length LH (1 byte) of the link layer packet to the LIPv4. Here,LT indicates a length of the link layer packet.

Referring to the illustrated equation, when a value of a length field ofIPv6 is LIPv6, LIPv6 indicates only a length of a payload of an IPpacket of IPv6, and thus a length of a link layer packet may be obtainedby adding a length of a header of a link layer packet and a length (40bytes) of a fixed header of IPv6. Here, LT may refer to a length of alink layer packet.

FIG. 10 is a diagram illustrating a procedure for encapsulating aconcatenated packet and an equation for calculating a length of a linklayer packet according to an embodiment of the present invention.

When an input IP packet is not within a processing range of a physicallayer, several IP packets may be concatenated to encapsulate one linklayer packet. The following description may be applied to an IP packetof IPv4 or IPv6 in the same way.

Several IP packets may form a payload of a link layer packet, a value ofthe packet type element may be 000B (IPv4) or 001B (IPv6), and a valueof a C/S field may be 01B (concatenated packet). A 3-bit count fieldindicating the number of IP packets included in one payload may bepositioned subsequent to the C/S field.

In order to obtain a length of a concatenated packet, the receiver mayuse a similar method to the case of a normal packet. When the number ofconcatenated IP packets indicated by a count field is n, a length of aheader of a link layer packet is LH, and a length of each IP packet isLk (here, 1≤k≤n), an entire length LT of the link layer packet may becalculated as shown in the illustrated equation.

Here, a concatenated packet has only information about a fixed header,and thus LH=1 (byte), and each Lk (1≤k≤n) value may be checked byreading a value of a length field present in a header of each IP packetincluded in the concatenated packet. The receiver may parse a lengthfield of a first IP packet at a point with a predetermined offset from apoint at which a header of a link layer packet ends and a payload isstarted and identify a length of the first IP packet using the lengthfield. The receiver may parse a length field of a second IP packet at apoint with a predetermined offset from a point at which the length ofthe first IP packet ends and identify the length of the second IP packetusing the length field. The above method may be repeated by as much asthe number of IP packets included in the payload of the link layerpacket so as to identify the length of the payload of the link layerpacket.

FIG. 11 is a diagram illustrating a procedure for obtaining a length ofa concatenated packet including an IPv4 packet and an equation forcalculating an offset value at which a length field of an IP packet ispositioned according to an embodiment of the present invention.

When an IP packet is input to a transmitter, it is not difficult to reada length field of an IP packet by the transmitter, but a receiver canknow only the number of IP packets included in a link layer packetthrough a header, and thus a position of each length field may not beknown. However, a length field is always positioned at the same positionin a header of the IP packet, and thus the position of the length fieldmay be retrieved so as to obtain a length of each IP packet included ina payload of a concatenated packet using the following method.

When n IP packets included in the payload of the concatenated packet areIP1, IP2, . . . , IPk, . . . , IPn, respectively, a length fieldcorresponding to IPk may be spaced apart from a start point of thepayload of the concatenated packet by Pk bytes. Here, Pk (1≤k≤n) is anoffset value indicating position of the length field of a k^(th) IPpacket beginning from the start point of the payload of the concatenatedpacket and may be calculated according to the shown equation.

Here, P1 of a packet of IPv4 may be 2 bytes. Accordingly, while P1 to Pkare sequentially updated, Lk corresponding thereto may be read andapplied to the aforementioned equation of FIG. 10 so as to finallyacquire a length of a concatenated packet.

FIG. 12 is a diagram illustrating a procedure for calculating a lengthof a concatenated packet including an IPv6 packet and an equation forcalculating an offset value indicating where a length field of an IPpacket is positioned, according to an embodiment of the presentinvention.

When the IPv6 packet is included in a payload of a link layer packet ina concatenated form, a procedure for obtaining a length of the payloadwill now be described. A length field contained in the IPv6 packet islength information about the payload of the IPv6 packet, and thus 40bytes as a length of a fixed header of IPv6 may be added to the lengthof the payload of the IPv6 packet, indicated by the length field, toacquire the length of the IPv6 packet.

When n IP packets included in the payload of the concatenated packet areIP1, IP2, . . . , IPk, . . . , IPn, respectively, a length fieldcorresponding to IPk may be spaced apart from a start point of thepayload of the concatenated packet by Pk bytes. Here, Pk (1≤k≤n) may bean offset value in which the length field of a k^(th) IP packet ispositioned from the start point of the payload of the concatenatedpacket and may be calculated according to the shown equation. Here, inthe case of IPv6, P1 may be 4 bytes. Accordingly, while P1 to Pk aresequentially updated, Lk corresponding thereto may be read and appliedto the aforementioned equation of FIG. 10 so as to finally acquire alength of a concatenated packet.

FIG. 13 is a diagram illustrating a procedure for encapsulating asegmented packet according to an embodiment of the present invention.

The following description may be applied to an IP packet of IPv4 or IPv6in the same way. One IP packet may be segmented into a payload of aplurality of link layer packets, a value of a packet type element may be000B (IPv4) or 001B (IPv6), and a value of the C/S field may be 10B or11B according to a configuration of a segment.

With regard to the C/S field, a C/S field value may be 11B only in asegment corresponding to a very last part of the IP packet and may be10B in all remaining segments. As described above, a value of the C/Sfield may indicate information about an extended header of a link layerpacket. That is, when a value of the C/S field is 10B, the C/S field mayhave a header with a length of 2 bytes, and when a value of the C/Sfield is 11 B, the C/S field may have a header with a length of 3 bytes.

In order to indicate that link layer packets are segmented from the sameIP packet, segment ID (Seg_ID) values included in headers of therespective link layer packets need to have the same value. In order toindicate sequence information of segments for recombination of a normalIP packet by a receiver, a Seg_SN value that is sequentially increasedmay be recorded in the headers of the respective link layer packets.

When an IP packet is segmented, a segment length may be determined andsegmentation may be performed based thereon, as described above. Then aSeg_Len_ID value corresponding to the corresponding length informationmay be recorded in a header. In this case, a length of a lastlypositioned segment may be changed compared with a previous segment, andthus length information may be directly indicated using an L_Seg_Lenfield.

Length information indicated using a Seg_Len_ID field and a L_Seg_Lenfield may indicate only information about a segment, that is, a payloadof a link layer packet, and thus the receiver may identify total lengthinformation of link layer packets by adding a header length of a linklayer packet to a payload length of the link layer packet with referenceto the C/S field.

FIG. 14 is a diagram illustrating a procedure for segmenting an IPpacket and header information of a link layer packet according to anembodiment of the present invention.

When the IP packet is segmented and encapsulated into a link layerpacket, field values allocated to headers of respective link layerpackets are shown in FIG. 14.

For example, if an IP packet having a length of 5500 bytes may be inputto a link layer in an IP layer, the IP packet may be segmented into fivesegments S1, S2, S3, S4, and S5, and headers H1, H2, H3, H4, and H5 maybe added to the segments S1, S2, S3, S4, and S5 to be encapsulated intorespective link layer packets.

In the case of an IPv4 packet, a value of a packet type element may bedetermined as 000B. A C/S field value of H1 to H4 may be 10B and a C/Sfield value of H5 may be 11B. All segment IDs (Seg_IDs) indicating thesame IP packet configuration may be 000B and Seg_SN fields maysequentially indicate 0000B to 0100B in H1 to H5.

Since a value obtained by dividing 5500 bytes by 5 is 1100 bytes, when asegment with a length of 1024 bytes closest to 1100 bytes is configured,a length of S5 as a last segment may be 1404 bytes (010101111100B). Inthis case, a Seg_Len_ID field may have a value of 0010B in theaforementioned example.

FIG. 15 is a diagram illustrating a procedure for segmenting an IPpacket including cyclic redundancy check (CRC) according to anembodiment of the present invention.

When an IP packet is segmented and transmitted to a receiver, atransmitter may attach CRC to end of the IP packet such that thereceiver can verify integrity of combined packets. In general, the CRCmay be attached to a last packet, and thus the CRC may be included inthe last segment after a segmentation procedure.

When the receiver receives data that exceeds a length of the lastsegment, the receiver may recognize the data as CRC. In addition, thereceiver may signal a length containing a length of the CRC as a lengthof the last segment.

FIG. 16 is a diagram illustrating a header structure of a link layerpacket when an MPEG-2 transport stream (TS) is input to a link layer,according to an embodiment of the present invention.

A packet type element may identify that an MPEG-2 TS packet is input toa link layer. For example, in this case, a value of the packet typeelement may be 011B.

The diagram illustrates a header structure of a link layer packet whenthe MPEG-2 TS is input. When the MPEG-2 TS packet is input to the linklayer, a header of the link layer packet may include a packet typeelement, a count field, a PID indicator (PI) field, and/or a deletednull packet indicator (DI) field.

For example, a count field of 2 bits or 3 bits, a PI field of 1 bit, anda DI of 1 bit may be subsequent to a packet type element of a header ofa link layer packet. When 2 bits are used as a count field, theremaining 1 bit may be reserved for future use. According to appositionof the reserved field, a fixed header part may be configured withvarious structures as illustrated in FIGS. 16(a) to 16(d). Although thepresent invention is described in terms of a header illustrated in FIG.16(a), the same description may also be applied to other types ofheaders.

When an MPEG-2 TS packet is input to a link layer, an extended headermay not be used in packet type=011.

A count field may identify the number of MPEG-2 TS packets contained ina payload of a link layer packet. A size of one MPEG-2 TS packet is verysmall compared with an input size of low-density parity-check (LDPC) asan FEC scheme that is likely to be employed in a physical layer of anext-generation broadcasting system, and thus concatenation of MPEG-2 TSpackets in a link layer may be basically considered. That is, one ormore MPEG-2 TS packets may be contained in a payload of a link layerpacket. However, the number of concatenated MPEG-2 TS packets may belimited so as to be identified with 2 bits or 3 bits. A length of anMPEG-2 TS packet has a predetermined size (e.g., 188 bytes), and thus areceiver can also infer a size of a payload of a link layer packet usinga count field. An example for determining the number of MPEG-2 TSpackets according to a count field value will be described later.

A common PID indicator (PI) field may be set to 1 when packetidentifiers (PIDs) of MPEG-2 TS packets contained in a payload of onelink layer packet are the same, and otherwise, the common PI field maybe set to 0. The common PI field may have a size of 1 bit.

A null packet deletion indicator (DI) field may be set to 1 when a nullpacket contained and transmitted in an MPEG-2 TS packet is deleted, andotherwise, the null packet DI may be set to 0. The null packet DI fieldmay have a size of 1 bit. When a DI field is 1, the receiver may reusesome fields of the MPEG-2 TS packet in order to support null packetdeletion in a link layer.

FIG. 17 is a diagram illustrating the number of MPEG-2 TS packetsincluded in a payload of a link layer packet according to a value of acount field, according to an embodiment of the present invention.

When the count field is 2 bits, there may be 4 cases with respect to thenumber of concatenated MPEG-2 TS packets. The size of the payload of thelink layer packet except for a sync byte (47 H) may also be identifiedby the count field.

The number of MPEG-2 TS packets allocated according to the number ofcount fields may be changed according to a system designer.

FIG. 18 is a diagram illustrating a header of an MPEG-2 TS packetaccording to an embodiment of the present invention.

The header of the MPEG-2 TS packet may include a sync byte field, atransport error indicator field, a payload unit start indicator field, atransport priority field, a PID field, a transport scrambling controlfield, an adaptation field control field, and/or a continuity counterfield.

The sync byte field may be used for packet synchronization and excludedduring encapsulation in a link layer. A transport error indicator (EI)positioned immediately after the sync byte field may not be used by atransmitter, and when an error incapable of being recovered occurs inthe receiver, the transport EI may be used to indicate the error to ahigher layer. Due to this purpose, the transport EI field may be a bitthat is not used by the transmitter.

When an error cannot be corrected in a stream, the transport EI fieldmay be field that is set during a demodulation process and indicatesthat there is an error that cannot be corrected in a packet.

The payload unit start indicator field may identify whether a packetizedelementary stream (PES) or program-specific information (PSI) isstarted.

The transport priority field may identify whether a packet has higherpriority than other packets having the same PID.

The PID field may identify a packet.

The transport scrambling control field may identify whether a scramblingis used and/or whether scrambling is used using an odd numbered key oran even numbered key.

The adaptation field control field may identify whether an adaptationfield is present.

The continuity counter field may indicate a sequence number of a payloadpacket.

FIG. 19 is a diagram illustrating a procedure for changing use of atransport EI field by a transmitter according to an embodiment of thepresent invention.

As illustrated, when a DI field is 1, a transport error indicator fieldmay be changed to be used as a deletion point indicator (DPI) field in alink layer of the transmitter. The DPI field may be restored to thetransport error indicator field after a null packet related processingis completed in the link layer of the receiver. That is, the DI fieldmay be a field that simultaneously indicates whether use of thetransport error indicator field is changed as well as whether a nullpacket is deleted.

FIG. 20 is a diagram illustrating a procedure for encapsulating anMPEG-2 TS packet according to an embodiment of the present invention.

Basically, the MPEG-2 TS packet is concatenated, and thus a payload ofone link layer packet may include a plurality of MPEG-2 TS packets, andthe number of the MPEG-2 TS packets may be determined according to theaforementioned method. When the number of MPEG-2 TS packets included ina payload of one link layer packet is n, each MPEG-2 TS packet may berepresented by Mk (1≤k≤n).

The MPEG-2 TS packet may include a fixed header of 4 bytes and a payloadof 184 bytes in general. 1 byte of a header of 4 bytes may be the syncbyte that has the same value 47 H. Accordingly, one MPEG-2 TS packet‘Mk’ may include a sync part S of 1 byte, a fixed header part Hk of 3bytes except for a sync byte, and/or a payload part Pk of 184 bytes(here, 1≤k≤n).

When the adaptation field is used in a header of the MPEG-2 TS packet,the fixed header part may be included in a portion immediately in frontof the adaptation field and the payload part may be included in theremaining adaptation part.

When n input MPEG-2 TS packets are [M1, M2, M3, . . . , Mn], the inputMPEG-2 TS packets may have arrangement of [S, H1, P1, S, H2, P2, . . . ,S, Hn, Pn]. The sync part may always have the same value, and in thisregard, even if the transmitter does not transmit the sync part, thereceiver may find a corresponding position in the receiver and re-insertthe sync part into the corresponding position. Accordingly, when apayload of a link layer packet is configured, the sync part may beexcluded to reduce the size of a packet. When a set of MPEG-2 TS packetshaving the above arrangement is configured with a payload of a linklayer packet, a header part and a payload part may be segmented with[H1, H2, . . . , Hn, P1, P2, . . . , Pn].

When a PI field value is 0, and a DI field value is 0, a length of apayload of a link layer packet is (n×3)+(n×184) bytes, and when 1 byteof a header length of the link layer packet is added, a total link layerpacket length may be obtained. That is, the receiver may identify alength of a link layer packet through this procedure.

FIG. 21 is a diagram illustrating a procedure for encapsulating MPEG-2TS packets having the same PIDs, according to an embodiment of thepresent invention.

When broadcasting data is continuously streamed, MD values of MPEG-2 TSsincluded in one link layer packet may be the same. In this case,repeated PID values may be simultaneously marked so as to reduce a sizeof a link layer packet. In this case, a PID indicator (PI) field in aheader of a link layer packet may be used.

A common PID indicator (PI) value of the header of the link layer packetmay be set to 1. As described above, in the payload of the link layerpacket, n input MPEG-2 TS packets [M1, M2, M3, . . . , Mn] may bearranged in [H1, H2, . . . , Hn, P1, P2, . . . , Pn] by excluding thesync part and segmenting a header part and a payload part. Here, thecase in which a header part [H1, H2, . . . , Hn] of the MPEG-2 TS hasthe same MD, and thus even if a PID is marked only once, the receivermay restore the PID to an original header. When a common PID is a commonPID (CPID) and a header obtained by excluding PID from a header Hk ofthe MPEG-2 TS packet is H′k (1≤k≤n), a header part [H1, H2, . . . , Hn]of the MPEG-2 TS included in a payload of a link layer packet isreconfigured as [CPID, H′1, H′2, H′n]. This procedure may be referred toas common PID reduction.

FIG. 22 is a diagram illustrating a common PID reduction procedure andan equation for obtaining a length of a link layer packet during thecommon PID reduction procedure, according to an embodiment of thepresent invention.

A header part of an MPEG-2 TS packet may include a PID with a size of 13bits. When MPEG-2 TS packets included in a payload of a link layerpacket have the same PID value, PIDs may be repeated by as much as thenumber of concatenated packets. Accordingly, a PID part may be excludedfrom a header part [H1, H2, . . . , Hn] of an original MPEG-2 TS packetto reconfigure [H′1, H′2, . . . , H′n], a value of the common PID may beset to a value of a common PID (CPID), and then the CIPD may bepositioned in front of the reconfigured header part.

The PID value may have a length of 13 bits, and a stuffing bit may beadded in order to form all packets in the form of a byte unit. Thestuffing bit may be positioned in front of or behind the CPID and may beappropriately arranged according to a configuration of otherconcatenated protocol layers or embodiments of a system.

In the case of encapsulation of MPEG-2 TS packets having the same PID,the PID may be excluded from the header part of the MPEG-2 TS packet andan encapsulation procedure is performed, and thus the length of apayload of a link layer packet may be obtained as follows.

As illustrated, a header of an MPEG-2 TS packet obtained by excludingthe sync byte may have a length of 3 bytes, and when a PID part of 13bits is excluded from the header of the MPEG-2 TS packet, the header ofthe MPEG-2 TS packet may be 11 bits. Accordingly, when n packets areconcatenated, the packets have (n×11) bits, and when the number ofconcatenated packets is set to a multiple of 8, (n×11) bits may be alength of a byte unit. Here, a stuffing bit with a length of 3 bits maybe added to 13 bits as a common PID length to configure a CPID part witha length of 2 bytes.

Accordingly, in the case of a link layer packet formed by encapsulatingn MPEG-2 TS packets having the same PID, when a header length of a linklayer packet is LH, a length of a CPID part is LCPID, and a total lengthof a link layer packet is LT, LT may be obtained according to the shownequation.

In the embodiment illustrated in FIG. 21, LH may be 1 byte and LCPID maybe 2 bytes.

FIG. 23 is a diagram illustrating the number of concatenated MPEG-2 TSpackets according to a value of a count field and a length of a linklayer packet according to the number when common PID reduction isapplied, according to an embodiment of the present invention.

When the number of concatenated MPEG-2 TS packets is determined, if allpackets have the same PID, the aforementioned common PID reductionprocedure may be applied, and the receiver may acquire a length of alink layer packet according to the equation described in relation to theprocedure.

FIG. 24 is a diagram illustrating a method for encapsulating an MPEG-2TS packet including a null packet, according to an embodiment of thepresent invention.

During transmission of the MPEG-2 TS packet, the null packet may beincluded in a transport stream for adjustment to a fixed transfer rate.The null packet is an overhead part in terms of transmission, and thuseven if a transmitter does not transmit the null packet, a receiver mayrestore the null packet. In order to delete and transmit the null packetby the transmitter and find and restore the number and position of thedeleted packets by the receiver, a null packet deletion indicator (DI)field in the header of the link layer packet may be used. In this case,a value of the null packet deletion indictor (DI) of the header of thelink layer packet may be set to 1.

Encapsulation when a null packet is positioned at an arbitrary pointbetween input transport streams may be performed by sequentiallyconcatenating n packets except for the null packet. The number ofcounted null packets that are continuously excluded may be contained ina payload of a link layer packet, and the receiver may generate and filla null packet in an original position based on the count value.

When n MPEG-2 TS packets except for the null packet are [M1, M2, M3, . .. , Mn], the null packet may be positioned at any position between M1 toMn. One link layer packet may include a counted number of null packetswith a number of times of 0 to n. That is, when a number of times thatnull packets are counted in one link layer packet is p, a range of p maybe 0 to n.

When a count value of null packets is Cm, a range of m may be 1≤m≤p, andwhen p=0, Cm is not present. As described above, MPEG-2 TS packetsbetween which Cm is positioned may be indicated using a field in aheader of the MPEG-2 TS packet, in which use of a transport errorindicator (EI) is changed to a deletion point indicator (DPI).

The present invention proposes a case in which Cm has a length of 1 byteand also considers a case in which Cm is extended when a packet has asufficient length for future use. Cm of 1-byte length may count amaximum of 256 null packets. A field that functions as an indicator of anull packet is positioned in a header of an MPEG-2 TS packet, and thuscalculation may be performed by excluding null packets by as much as avalue obtained by adding 1 to a value indicated by Cm. For example, inthe case of Cm=0, one null packet may be excluded, and in the case ofCm=123, 124 null packets may be excluded. When continuous null packetsexceed 256, a 257^(th) null packet may be processed as a normal packet,and next null packets may be processed as null packets using theaforementioned method.

As illustrated, when null packets may be positioned between MPEG-2 TSpackets corresponding to Mi and Mi+1, a counted number of the nullpackets is C1, and when a null packet is positioned between MPEG-2 TSpackets corresponding to Mj and Mj+1, a counted number of the nullpackets is Cp, and in this case, an actual transmission sequence may be[ . . . , Mi, C1, Mi+1, Mj, Cp, Mj+1, . . . ].

In a procedure for segmenting and reordering a header part and a payloadpart of an MPEG-2 TS packet instead of a null packet in order toconfigure a payload of a link layer packet, a count value Cm (1≤m≤p) ofnull packets may be disposed between the header part and the payload ofthe MPEG-2 TS packet. That is, the payload of the link layer packet maybe disposed like [H1, H2, . . . , Hn, C1, . . . , Cp, P1, P2, . . . ,Pn], and a receiver may sequentially check a count value on abyte-by-byte basis at an order indicated in a DPI field of Hk andrecover a null packet in an original order of an MPEG-2 TS packetcorresponding to the count value.

FIG. 25 is a diagram illustrating a procedure for processing anindicator for counting deleted null packets and an equation forobtaining a length of a link layer packet during the procedure,according to an embodiment of the present invention.

A value of a DPI field may be set to indicate that null packets aredeleted and a count value of the deleted null packets is present. Asillustrated, when a value of a DPI field in Hi of a header of aplurality of MPEG-2 TS packets is 1, this may indicate that the MPEG-2TS packets are encapsulated by excluding a null packet between Hi andHi+1 and 1-byte count value according thereto is positioned between aheader part and a payload part.

During this procedure, a length of a link layer packet may be calculatedaccording to the shown equation. Accordingly, in the case of a linklayer packet obtained by encapsulating n MPEG-2 TS packets from which anull packet is excluded, when a header length of the link layer packetis LH, a length of a count value Cm (1≤m≤p) of a null packet is LCount,and a total length of the link layer packet is LT, LT may be acquiredaccording to the shown equation.

FIG. 26 is a diagram illustrating a procedure for encapsulating anMPEG-2 TS packet including a null packet, according to anotherembodiment of the present invention.

In another encapsulation method for excluding a null packet, a payloadof a link layer packet may be configured. According to anotherembodiment of the present invention, in a procedure for segmenting andreordering a header part and a payload part of an MPEG-2 TS packet inorder to configure a payload of a link layer packet, a count value Cm(1≤m≤p) of null packets may be positioned in a header part and an orderof the null packets may be maintained. That is, a header of each MPEG-2TS may include a count value of null packets at a point at which aheader ends. Accordingly, upon reading a value of a DPI field containedin a header of each MPEG-2 TS and determining that the null packets aredeleted, the receiver may read a count value contained in a last part ofthe corresponding header, regenerate null packets by as much as thecorresponding count value, and contain the null packets in a stream.

FIG. 27 is a diagram illustrating a procedure for encapsulating MPEG-2TS packets including the same packet identifier (PID) in a streamincluding a null packet, according to an embodiment of the presentinvention.

According to an embodiment of the present invention, in a streamincluding null packets, a procedure for encapsulating MPEG-2 TS packetsincluding the same packet identifier (PID) may be performed by combininga procedure for encapsulating a link layer packet by excluding theaforementioned null packet and a procedure for encapsulating MPEG-2 TSpackets having the same PID as a link layer packet.

Since null packets are allocated separate PIDs indicating the respectivenull packets, when the null packets are contained in an actual transportstream, the null packets are not processed with the same PID. However,after a procedure for excluding a null packet is performed, since only acount value of null packets is contained in a payload of a link layerpacket, the remaining n MPEG-2 TS packets have the same PID, and thusthe null packets may be processed using the aforementioned method.

FIG. 28 is a diagram illustrating an equation for obtaining a length ofa link layer packet while MPEG-2 TS packets including the same packetidentifier (PID) are encapsulated in a stream including a null packet,according to an embodiment of the present invention.

While MPEG-2 TS packets including the same packet identifier (PID) areencapsulated in a stream including null packets, a length of a linklayer packet may be derived according to the equations of FIG. 22 and/orFIG. 25. These equations may be summarized as illustrated.

FIG. 29 is a diagram illustrating a configuration of a link layer packetfor signaling transmission, according to an embodiment of the presentinvention.

In order to transmit signaling information as well as information aboutupdate of IP header encapsulation information and broadcast channel scaninformation prior to reception of an IP packet or an MPEG-2 TS packet bya receiver, the present invention proposes a packet form fortransmitting signaling (e.g., signaling data) to a link layer.

According to an embodiment of the present invention, when a value of apacket type element included in a header of a link layer packet is‘110B’, a section table (or a descriptor) for signaling may be containedand transmitted in a payload of a link layer packet. The signalingsection table may include a signaling table/table section included inDVB-service information (SI), PSI/PSIP, non real time (NRT), ATSC 2.0,and mobile/handheld (MH), which are conventionally used.

FIG. 30 is a diagram illustrating a configuration of a link layer packetfor transmission of a framed packet, according to an embodiment of thepresent invention.

A packet used in a general network other than an IP packet or an MPEG-2TS packet may be transmitted through a link layer packet. In this case,a packet type element of a header of a link layer packet may have avalue of ‘111B’, and the value may indicate that a framed packet isincluded in a payload of a link layer packet.

FIG. 31 is a diagram illustrating syntax of a framed packet according toan embodiment of the present invention.

The syntax of the framed packet may include ethernet_type, length,and/or packet( ) fields. The ethernet_type field of 16 bits may identifya type of a packet in the packet( ) field according to an IANA registry.Here, only the registered values may be used. The length field of 16bits may set a total length of a packet( ) configuration in bytes. Thepacket( ) field with a variable length may include a network packet.

FIG. 32 is a diagram illustrating a receiver of a next-generationbroadcast system, according to an embodiment of the present invention.

The receiver according to an embodiment of the present invention mayinclude a receiving unit (not shown), a channel synchronizer 32010, achannel equalizer 32020, a channel decoder 32030, a signaling decoder32040, a baseband operation controller 32050, a service map database(DB) 32060, a transport packet interface 32070, a broadband packetinterface 32080, a common protocol stack processor 32090, a servicesignaling channel processing buffer & parser 32100, an audio/video (AN)processor 32110, a service guide processor 32120, an applicationprocessor 32130, and/or a service guide DB 32140.

The receiver (not shown) may receive a broadcast signal.

The channel synchronizer 32010 may synchronize a symbol frequency andtiming so as to decode a signal received on a baseband. Here, thebaseband may refer to a region in which a broadcast signal istransmitted and received.

The channel equalizer 32020 may perform channel equalization on areceived signal. The channel equalizer 32020 may compensate for thereceived signal when the received signal is distorted due to multipathpropagation, the Doppler effect, and so on.

The channel decoder 32030 may restore the received signal to a transportframe. The channel decoder 32030 may perform forward error detection(FEC) on data or a transport frame contained in the received signal.

The signaling decoder 32040 may extract and decode signaling datacontained in the received signal. Here, the signaling data may includesignaling data and/or service information (SI), which will be describedlater.

The baseband operation controller 32050 may control signal processing ina baseband.

The service map DB 32060 may store signaling data and/or serviceinformation. The service map DB 32060 may store signaling data containedand transmitted in a broadcast signal and/or signaling data containedand transmitted in a broadband packet.

The transport packet interface 32070 may extract a transport packet froma transport frame or a broadcast signal. The transport packet interface32070 may extract signaling data or an IP datagram from the transportpacket.

The broadband packet interface 32080 may receive a broadcast relatedpacket through the Internet. The broadband packet interface 32080 mayextract a packet acquired through the Internet and combine or extractsignaling data or A/V data from the corresponding packet.

The common protocol stack processor 32090 may process a received packetaccording to a protocol contained in a protocol stack. For example, thecommon protocol stack processor 32090 may perform processing in eachprotocol to process the received packet using the aforementioned method.

The service signaling channel processing buffer & parser 32100 mayextract signaling data contained in the received packet. The servicesignaling channel processing buffer & parser 32100 may extract signalinginformation associated with scan and/or acquisition of a service and/orcontent from an IP datagram and so on and may parse the signalinginformation. Signaling data in the received packet may be present at apredetermined position or channel. The position or channel may bereferred to as a service signaling channel. For example, the servicesignaling channel may have a specific IP address, a UDP port number, atransport session identifier, and so on. The receiver may recognize datatransmitted with the specific IP address, the UDP port number, thetransport session, and so on as signaling data.

The A/V processor 32110 may perform decoding and presentation processingon received A/V data.

The service guide processor 32120 may extract announcement informationfrom the received signal, manage the service guide DB 32140, and providea service guide.

The application processor 32130 may extract application data and/orapplication related information contained in the received packet andprocess the application data and/or application related information.

The service guide DB 32140 may store service guide data.

FIG. 33 is a diagram illustrating normal format of a section tableaccording to an embodiment of the present invention.

According to an embodiment of the present invention, the section tablemay include a table_id field, a section_syntax_indicator field, asection_length field, a version_number field, a current_next_indicatorfield, a section_number field, a last_section_number field, and/or asection data field.

The table_id field may indicate a unique ID value of a correspondingtable.

The section_syntax_indicator field may indicate a format of a tablesection subsequent to a corresponding field. When a value of thecorresponding field is 0, the value may indicate that a correspondingtable section is a short format. When a value of the corresponding fieldis 1, the corresponding table section follows a normal long format.According to an embodiment of the present invention, a correspondingfield value may always have a fixed value 1.

The section_length field may indicate a length of a correspondingsection. A length to a last part of the corresponding section from anext field of the corresponding field may be indicated in bytes.

The version_number field may indicate a version of a correspondingtable.

When a value of the current_next_indicator field is 1, the value mayindicate that a corresponding section table is effective, and when thevalue is 0, the value may indicate that a section table for nexttransmission is effective.

The section_number field may indicate a number of a section included inthe corresponding table. In the case of a first section contained in thecorresponding table, a value of the section_number field may be 0 andmay be gradually increased.

The last_section_number field may refer to a number of a last sectionamong sections included in a corresponding table.

The section data field may include data including a correspondingsection.

In the drawing, a field denoted by Specific Use may refer to a fieldthat is differently configured according to each table. A bit numberallocated to the field denoted by Specific Use may be maintained.

FIG. 34 is a diagram illustrating a structure of a link layer packet fortransmission of signaling, according to an embodiment of the presentinvention.

According to an embodiment of the present invention, when signalinginformation is transmitted using a link layer packet, a value of apacket type element may indicate 110B.

The drawing illustrates a structure of a header of a link layer packetduring transmission of signaling. Referring to the drawing, whensignaling is transmitted, a signaling type field of 2 bits is presentbehind the packet type element. The signaling type field may indicate atype of signaling to be transmitted. According to a signaling typefield, information of the remaining 3-bit parts of a fixed headersubsequent thereto and information about an extended header may bedetermined.

According to an embodiment of the present invention, when a value of asignaling type field is 00B, a signaling type is a section table type.In the case of the section table, a field contained in the tablecontains information about segmentation of a section and informationabout a length of the section, and thus the link layer packet mayindicate only a packet type and a signaling type and be transmittedwithout separate processing. When the signaling type is a section tableform, the remaining 3 bits obtained by excluding a packet type elementand a signaling type field from a fixed header part may be reserved forfuture use without being used. When the signaling type is a sectiontable form, an extended header is not basically used, but when a lengthof a link layer packet needs to be indicated, an extended header of 1 or2 bytes may be added and used as a length field.

According to an embodiment of the present invention, when a value of asignaling type field is 01B, the value may indicate that a signalingtype is a descriptor form. In general, the descriptor may be used as apart of the section table, and the descriptor corresponds to simplesignaling, and thus the descriptor may be transmitted in a correspondingsignaling type in order to transmit only the descriptor. The descriptormay have a shorter length than the section table, and thus a pluralityof descriptors may be contained and transmitted in one link layerpacket. According to an embodiment of the present invention, 3 bitscorresponding to an indicator part of a fixed header may be used toindicate the number of descriptors contained in one link layer packet.When a signaling type is a descriptor type, the length of the link layerpacket may be indicated using information about the length of thecorresponding descriptor, contained in the descriptor, without using anextended header. When the length of the link layer packet needs to beseparately indicated, an extended header of 1 or 2 bytes may be addedand used as a length field.

According to an embodiment of the present invention, a signaling typefield value 10B may be reserved for another type of signaling for futureuse.

According to an embodiment of the present invention, when a value of asignaling type field is 11B, the value may indicate that a signalingtype is GSE-LLC. The GSE-LLC signaling may have a structure to besegmented. Accordingly, when a signaling type is GSE-LLC, the remaining3-bit fields obtained by excluding a packet type element and a signalingtype field from a fixed header part may be used as a segment ID. When asignaling type is GSE-LLC, an extended header of 2 bytes may be added,and the aforementioned extended header of 2 bytes may include a segmentsequence number (Seg_SN) of 4 bits and a length field of 12 bits.

According to an embodiment of the present invention, GSE-LLC stands forgeneric stream encapsulation logical link control and may refer to oneof two attached layers of a data link layer of an OSI model.

FIG. 35 is a diagram illustrating meaning of a value denoted by asignaling type field and contents of a fixed header and extended headersubsequent to the signaling type field, according to an embodiment ofthe present invention.

According to an embodiment of the present invention, when a value of thesignaling type field is 00B, a field subsequent to the signaling typefield may not be present.

According to an embodiment of the present invention, when a value of thesignaling type field is 01B, a concatenation count field may be presentafter the signaling type field. The concatenation count field may bepresent when only a descriptor instead of a section table istransmitted. The concatenation count field may indicate the number ofdescriptors contained in a payload of a link layer packet. Theconcatenation count field will be described in detail.

According to an embodiment of the present invention, when a value of thesignaling type field is 11B, a segment ID (Seg_ID) field, a segmentsequence number (Seg_SN) field, and/or a length field may be presentafter the signaling type field. In the case of LLC signaling data thatcan be transmitted using DVB_GSE, the LLC signaling data may beautonomously segmented. The segment ID (Seg_ID) field may refer to an IDfor identifying a segmented segment when LLC data is segmented. Whensegments of the transmitted LLC data are combined into one, a receivingside may recognize that segments of each LLC data item are components ofthe same LLC data using a segment ID (Seg_ID) field. The segment ID(Seg_ID) may have a size of 3 bits and identify 8 segmentations. Thesegment sequence number (Seg_SN) field may refer to a sequence of eachsegment when LLC data is segmented. Since a front part of the LLC datacontains an index of a corresponding data table, when a receiverreceives packets, segmented segments need to be sequentially aligned.Link layer packets having payloads segmented from one LLC data item havethe same Seg_ID but have different Seg_SNs. The segment sequence number(Seg_SN) field may have a size of 4 bits. One LLC data item may besegmented into a maximum of 16 segments. The length field may indicate alength of LLC data corresponding to a payload of a current link layerpacket in a byte unit. Accordingly, a total length of the link layerpacket may be a value obtained by adding 3 bytes as a header length to avalue indicated by the length field.

According to an embodiment of the present invention, DVB_GSE may standfor DVB-generic stream encapsulation and refer to a data link layerprotocol defined by DVB.

FIG. 36 is a diagram illustrating the number of descriptors included ina payload of a link layer packet according to a concatenation countvalue, according to an embodiment of the present invention.

According to an embodiment of the present invention, the concatenationcount value may indicate that descriptors, the number of which isobtained by adding 1 to a value of the concatenation count field, areincluded in a payload of one link layer packet. Accordingly, 3 bits areallocated to the concatenation count field, and thus a maximum of 8descriptors may be signaled to constitute one link layer packet.

FIG. 37 is a diagram illustrating a procedure for encapsulating asection table in a payload when signaling information input to a payloadof a link layer packet is a section table, according to an embodiment ofthe present invention.

According to an embodiment of the present invention, one section tableis a payload of a link layer packet without change, and in this case, avalue indicated by a packet type element is 110B (signaling), and avalue indicated by a signaling type field may be 00B (section table). Inthe drawing, the remaining 3 bits obtained by excluding a packet typeelement and a signaling type field from a fixed header may be reservedfor future use.

According to an embodiment of the present invention, fields contained inthe section table may include a field indicating a length of acorresponding section. The aforementioned field indicating the length ofthe corresponding section is always positioned in the same position inthe section table, and thus a field present in a point spaced apart froma start point of a payload of a link layer packet by a predeterminedoffset may be checked to identify a length of the payload. In the caseof a section table, a section_length_field with a length of 12 bits ispresent at a position spaced apart from a point at which a payload isstarted by 12 bits. The section_length_field may indicate a length to alast part of the section immediately after the section_length_field.Accordingly, a length of a part that is not included in thesection_length_field and a length of a header of a link layer packet maybe added to a value indicated by the section_length_field so as toderive a total length of a link layer packet. Here, the part (3 bytes)that is not included in the section_length_field may include a length ofa table_id field and section_length_field. In addition, the length of aheader of a link layer packet may be 1 byte. That is, a total length ofthe link layer packet may be a value obtained by adding 4 bytes to avalue indicated by the section_length_field.

According to an embodiment of the present invention, upon receiving alink layer packet including a section table, a reception apparatuses mayacquire and use information about the corresponding section tablethrough a value of a table_id field with a length of 8 bits, which isimmediately after a fixed header of a link layer packet.

FIG. 38 is a diagram illustrating syntax of a network information table(NIT) according to an embodiment of the present invention.

According to an embodiment of the present invention, when a sectiontable for signaling is included and transmitted in a payload of a linklayer packet, a network information table indicating current broadcastnetwork related information as a section table may be included in apayload of a link layer packet.

According to an embodiment of the present invention, the networkinformation table may include a table_id field, asection_syntax_indicator field, a section_length field, a network_idfield, a version_number field, a current_next_indicator field, asection_number field, a last_section_number field, anetworkdescriptors_length field, a descriptor( ) atransport_stream_loop_length field, a broadcast_id field, anoriginal_network_id field, a delivery_system_descriptor_length field,and/or a delivery_system_descriptorO.

According to an embodiment of the present invention, a description of afield having the same name as a field described with reference to adiagram illustrating a normal format of the aforementioned section tableamong fields contained in the network information table will besubstituted with the above description.

The network_id field may indicate a unique identifier of a currentlyused broadcast network.

The network_descriptors_length field may indicate a length of adescriptor that states network related information at a network level.

The descriptor( ) may indicate a descriptor that states network relatedinformation in a network level.

The transport_stream_loop_length field may indicate a length of streamrelated information transmitted in a broadcast network.

The broadcast_id field may indicate a unique identifier of a broadcaststation present in a used broadcast network.

The original_network_id field may indicate a unique identifier of anoriginally used broadcast network. When the originally used broadcastnetwork is different from a currently used broadcast network, NIT mayinclude information about the originally used broadcast network throughthe original_network_id field.

The delivery_system_descriptor_length field may indicate a length of adescriptor that states detailed information related to a delivery_systemin a current broadcast network.

The delivery_system_descriptor( ) may indicate a descriptor includingdetailed information related to a delivery_system in a current broadcastnetwork.

FIG. 39 is a diagram illustrating syntax of a delivery system descriptorincluded in a network information table (NIT), according to anembodiment of the present invention.

According to an embodiment of the present invention, the delivery systemdescriptor may include information about a physical layer pipe (PLP) fortransmitting signaling data and so on, related to data items transmittedby a specific broadcast station in a delivery system.

According to an embodiment of the present invention, the delivery systemdescriptor may include a descriptor_tag field, a descriptor_lengthfield, a delivery_system_id field, a base_PLP_id field, abase_PLP_version field, and/or a delivery_system_parameters( ).

The descriptor_tag field may indicate an identifier indicating that acorresponding descriptor is a delivery system descriptor.

The descriptor_length field may indicate a length of a correspondingdescriptor.

The delivery_system_id field may indicate a unique delivery systemidentifier of a used broadcast network.

The base_PLP_id field may indicate an identifier of a representativephysical layer pipe (PLP) for decoding components for configuring abroadcast service transmitted from a specific broadcast stationidentified by the broadcast_id. Here, the PLP may refer to a data pipeof a physical layer and a broadcast service transmitted from a specificbroadcast station may include PSI/SI information and so on.

The base_PLP_version field may indicate version information according tochange in data transmitted through a PLP identified according to thebase_PLP_id. For example, when service signaling such as PSI/SI istransmitted through the base_PLP, a value of the base_PLP_version fieldmay be incremented by 1 whenever service signaling is changed.

The delivery_system_parameters( ) may include a parameter indicatingbroadcast transmitting system characteristics. The parameter may includea bandwidth, a guard interval, a transmission mode, a center frequency,and so on.

FIG. 40 is a diagram illustrating syntax of a fast information table(FIT) according to an embodiment of the present invention.

According to an embodiment of the present invention, when a sectiontable for signaling is included and transmitted in a payload of a linklayer packet, a fast information table (FIT) as a section table may beincluded in the payload of the link layer packet. According to anembodiment of the present invention, a reception apparatus may rapidlyand easily scan and acquire a broadcast service through the FIT.

According to an embodiment of the present invention, the FIT may includea table_id field, a private_indicator field, a section_length field, atable_id_extension field, a FIT_data_version field, acurrent_next_indicator field, a section_number field, alast_section_number field, a num_broadcast field, a broadcast_id field,a delivery_system_id field, a base_PLP_id field, a base_PLP_versionfield, a num_service field, a service_id field, a service_categoryfield, a service_hidden_flag field, an SP_indicator field, anum_component field, a component_id field, and/or a PLP_id field.

According to an embodiment of the present invention, a description of afield having the same name as a field described with reference to adiagram illustrating a normal format of the aforementioned section tableamong fields contained in the FIT will be substituted with the abovedescription.

The table_id field may indicate that a corresponding table includesinformation related to rapid scan of a service and indicate that thecorresponding table corresponds to a fast information table.

The private_indicator field may always be set to 1.

The table_id_extension field may provide a scope of reserved fields thatlogically correspond to a portion of the table_id field.

The FIT_data_version field may indicate syntax included in a fastinformation table and version information about semantics. According toan embodiment of the present invention, a reception apparatus maydetermine whether signaling contained in a corresponding table isprocessed using the FIT_data_version field.

The num_broadcast field may indicate the number of broadcast stationsthat transmit a broadcast service or content through a frequency or atransmitted transport frame.

The broadcast_id field may indicate a unique identifier of a broadcaststation that transmits a broadcast service or content through afrequency or a transmitted transport frame. In the case of a broadcaststation that transmits MPEG-2 TS-based data, the broadcast_id may havethe same value as the transport_stream_id of MPEG-2 TS.

The delivery_system_id field may indicate an identifier of a broadcasttransmitting system that applies and processes the same transportparameter in a used broadcast network.

The base_PLP_id field may indicate an identifier of a PLP fortransmitting broadcast service signaling transmitted by a specificbroadcast station identified by the broadcast_id. The base_PLP_id fieldmay indicate an identifier of a representative physical layer pipe (PLP)for decoding components included in a broadcast service transmitted by aspecific broadcast station identified by the broadcast_id. Here, the PLPmay refer to a data pipe of a physical layer and the broadcast servicetransmitted by a specific broadcast station may include PSI/SIinformation and so on.

The base_PLP_version field may refer to version information according tochange in data transmitted through a PLP identified by the base_PLP_id.For example, when service signaling such as PSI/SI is transmittedthrough the base_PLP, a value of the base_PLP_version field may beincremented by 1 whenever service signaling is changed.

The num_service field may refer to the number of broadcast servicestransmitted by a broadcast station identified by the broadcast_id in acorresponding frequency or a transport frame.

The service_id field may refer to an identifier for identifying abroadcast service.

The service_category field may refer to a category of a broadcastservice. For example, when a value of the service_category field is0x01, the value may indicate a basic TV, when the value is 0x02, thevalue may indicate a basic radio, when the value is 0x03, the value mayindicate an RI service, when the value is 0x08, the value may indicate aservice guide, and when the value is 0x09, the value may indicateemergency alert.

The service_hidden_flag field may indicate whether a correspondingbroadcast service is hidden. When the service is hidden, thecorresponding service is a text service or a service that isautonomously used, and thus a reception apparatus according to anembodiment of the present invention may ignore the aforementioned hiddenbroadcast service or hide the broadcast service in a service list.

The SP_indicator field may indicate whether service protection isapplied to one or more components in a corresponding broadcast service.

The num_component field may indicate the number of components includedin a corresponding broadcast service.

The component_id field may indicate an identifier for identifying acorresponding component in a broadcast service.

The PLP_id field may indicate an identifier for identifying a PLP fortransmitting a corresponding component in a broadcast service.

FIG. 41 is a diagram illustrating a procedure for encapsulating adescriptor in a payload when signaling information input to a payload ofa link layer packet is a descriptor, according to an embodiment of thepresent invention.

According to an embodiment of the present invention, one or moredescriptors may be included in the payload of the link layer packet, andin this case, a value indicated by the packet type element may be 110B(signaling), and a value indicated by the signaling type field may be01B (descriptor). In the drawing, the remaining 3 bits obtained byexcluding a packet type element and a signaling type field from a fixedheader may indicate a count field indicating the number of descriptorscontained in a payload of one link layer packet. The payload of one linklayer packet may include a maximum of 8 descriptors.

According to an embodiment of the present invention, all descriptors mayinclude a descriptor_tag field of 1 byte and a descriptor_length fieldof 1 byte in a start part of the descriptor. According to an embodimentof the present invention, a length of a concatenated packet may beobtained using the aforementioned descriptor_length field. Thedescriptor_length field is always positioned at the same position in adescriptor, and thus a field at a position spaced apart from a startpoint of a payload of a link layer packet by a predetermined offset maybe checked so as to recognize a length of the payload. In the case of adescriptor, the descriptor_length field with a length of 8 bits may bepresent a position spaced apart from a start point of the payload by 8bits. The descriptor_length field may indicate a length to a last partof the descriptor immediately after the corresponding field.Accordingly, a length (1 byte) of a part that is not included in thedescriptor_length field and a length (1 byte) of the descriptor_lengthfield may be added to a value indicated by the descriptor_length fieldso as to derive a length of one descriptor. In addition, lengths ofrespective descriptors may be added by as much as the number ofdescriptors indicated by the count field so as to derive a total lengthof the link layer packet. For example, according to an embodiment of thepresent invention, a second descriptor included in a payload of a linklayer packet may be started at a position spaced apart from an initialpart of the payload by as much as a length of a first descriptor and adescriptor_length field of the second descriptor is present at aposition spaced apart from the position at which the descriptor isstarted by a predetermined offset, and in this regard, the field may bechecked so as to derive a total length of the second descriptor. Duringthis process, each of a length of each of one or more descriptorsincluded in the payload of the link layer packet may be derived, and thesum of lengths of respective descriptors and a length of a header of alink layer packet may be added so as to derive a total length of thelink layer packet.

According to an embodiment of the present invention, upon receiving alink layer packet including one or more descriptors, a receptionapparatus may acquire and use signaling information included in eachdescriptor through a value of the descriptor_tag field with a length of8 bits, included in each descriptor.

FIG. 42 is a diagram illustrating syntax of a fast informationdescriptor according to an embodiment of the present invention.

According to an embodiment of the present invention, when a descriptorfor signaling is included and transmitted in a payload of a link layerpacket, the fast information descriptor may be included in the payloadof the link layer packet. According to an embodiment of the presentinvention, a reception apparatus may rapidly and easily scan and acquirea broadcast service through the fast information descriptor.

According to an embodiment of the present invention, the fastinformation descriptor may include a descriptor_tag field, adescriptor_length field, a num_broadcast field, a broadcast_id field, adelivery_system_id field, a base_PLP_id field, a base_PLP_version field,a num_service field, a service_id field, a service_category field, aservice_hidden_flag field, and/or an SP_indicator field.

According to an embodiment of the present invention, a description of afield having the same name as a field included in the aforementioned FITamong fields contained in the FIT will be substituted with the abovedescription.

The descriptor_tag field may indicate that the corresponding descriptoris a fast information descriptor containing information related to rapidservice scan.

The descriptor_length field may indicate a length of a correspondingdescriptor.

FIG. 43 is a diagram illustrating a delivery system descriptor accordingto an embodiment of the present invention.

According to an embodiment of the present invention, when a descriptorfor signaling is included and transmitted in a payload of a link layerpacket, a delivery system descriptor may be included in the payload ofthe link layer packet. The delivery system descriptor m may includeinformation about a physical layer pipe (PLP) for transmitting signalingdata and so on associated with data items transmitted by a specificbroadcast station in a delivery system.

According to an embodiment of the present invention, the delivery systemdescriptor may include a descriptor_tag field, a descriptor_lengthfield, a delivery_system_id field, a num_broadcast field, a base_PLP_idfield, a base_PLP_version field, a delivery_system_parameters_lengthfield, and/or delivery_system_parameters( ).

The descriptor_tag field may indicate that a corresponding descriptor isa delivery system descriptor.

The descriptor_length field may indicate a length of a correspondingdescriptor.

The delivery_system_id field may indicate an identifier for identifyinga delivery system using the same parameter in a used broadcast network.

The num_broadcast field may indicate the number of broadcast stationsthat transmit a broadcast service or content through a frequency or atransmitted transport frame.

The base_PLP_id field may indicate an identifier of a representativephysical layer pipe (PLP) for decoding components included in abroadcast service transmitted by a specific broadcast station identifiedby the broadcast_id. Here, the PLP may refer to a data pipe of aphysical layer, and the broadcast service transmitted from the specificbroadcast station may include PSI/SI information and so on.

The base_PLP_version field may indicate version information according tochange in data transmitted through a PLP identified by the base_PLP_id.For example, when service signaling such as PSI/SI is transmittedthrough the base_PLP, a value of the base_PLP_version field may beincremented by 1 whenever service signaling is changed.

The delivery_system_parameters_length field may indicate a length of adelivery_system_parameters( ) subsequent to a corresponding field.

The delivery_system_parameters( ) may include a parameter indicatingbroadcast transmitting system characteristics. The parameter may includea bandwidth, a guard interval, a transmission mode, a center frequency,and so on.

According to an embodiment of the present invention, the delivery systemdescriptor may be included and transmitted in the aforementioned networkinformation table (NIT). Syntax of the delivery system descriptor whenthe delivery system descriptor is included and transmitted in thenetwork information table has been described above in the description ofthe network information table.

FIG. 44 is a diagram illustrating a procedure for encapsulating oneGSE-LLC item in a payload of one link layer packet when signalinginformation input to a payload of a link layer packet is a GSE-LLC typeused in the DVB-GSE standard, according to an embodiment of the presentinvention.

According to an embodiment of the present invention, the LLC data may bedivided into an index part and a record part, and the record part may bere-divided into several tables. Here, a table included in the recordpart may have a GSE table structure or a normal section table structure.

In the drawing, according to an embodiment of the present invention, oneLLC item may be a payload of one link layer packet, and in this case, avalue indicated by the packet type element may be 110B (signaling), anda value indicated by the signaling type field may be 11B (GSE-LLC).According to an embodiment of the present invention, when GSE-LLC typeof signaling is transmitted, the link layer packet may have an extendedheader of 2 bytes, and the aforementioned extended header of 2 bytes mayinclude a segment sequence number (Seg_SN) field of 4 bits and a lengthfield of 12 bits. The aforementioned length field may be allocated avalue indicating a total length of a link layer packet according to asystem configuration or allocate a value indicating a length of only apayload of a link layer packet.

FIG. 45 is a diagram illustrating a procedure for encapsulating oneGSE-LLC data item in payloads of a plurality of link layer packets whensignaling information input to a payload of a link layer packet is aGSE-LLC type used in the DVB-GSE standard, according to an embodiment ofthe present invention.

According to an embodiment of the present invention, when the LLC datais segmented, values of the Seg_ID field may be the same in order toindicate that data is segmented from the same LLC data.

According to an embodiment of the present invention, the Seg_SN fieldmay include sequence information of the segmented segments such that areception apparatus receives the segmented LLC data and recombines thesegmented data in a proper order. When one LLC data item is included ina payload of one link layer packet, a value of the Seg_SN field may be0.

According to an embodiment of the present invention, a receptionapparatus may recognize the number of segments obtained by segmentingthe LLC data with respect to the corresponding Seg_ID through the LLCindex part.

FIG. 46 is a diagram illustrating a method for transmitting signalinginformation according to an embodiment of the present invention.

According to an embodiment of the present invention, the signalinginformation transmission method may include generating a link layerpacket including signaling information (S14010) and/or transmitting thegenerated link layer packet (S14020). In the generating of the linklayer packet including the signaling information (S14010), the linklayer packet may include a fixed header and a payload, and the signalinginformation may include information about a broadcast program and dataand information required to receive a broadcast program and data. Inaddition, the signaling information may be included in a payload of alink layer packet. The aforementioned fixed header may include a packettype element for identifying a type of data included in a payload of alink layer packet according to an embodiment of the present inventionand a signaling type element for identifying a type of signalinginformation included in the payload of the link layer packet accordingto an embodiment of the present invention. A transmitting side maytransmit the link layer packet generated via the aforementionedprocedure (S14020). The link layer packet, the packet type element, andthe signaling type element have been described above in detail.

According to another embodiment of the present invention, a type ofsignaling information identified by the aforementioned signaling typeelement may be a section table.

According to another embodiment of the present invention, a type ofsignaling information identified by the aforementioned signaling typeelement may be a descriptor.

According to another embodiment of the present invention, a type ofsignaling information identified by the aforementioned signaling typeelement may be GSE-LLC. The signaling type element has been describedabove in detail.

According to another embodiment of the present invention, when one ormore descriptors are included in a payload of one link layer packet, theaforementioned fixed header may include a concatenation count fieldindicating the number of descriptors included in the payload of one linklayer packet. The count field has been described above in detail.

According to another embodiment of the present invention, when GSE-LLCdata is segmented into one or more segments and one segment of one ormore segments is included in a payload of one link layer packet, theaforementioned fixed header may include a segment identification elementfor identifying GSE-LLC to which a segment included in a payload of alink layer packet belongs. The segment identification element has beendescribed above in detail.

According to another embodiment of the present invention, theaforementioned link layer packet may include an extended header, and theaforementioned extended header may include a segment sequence elementindicating segment sequence information included in a payload of a linklayer packet, required for recombination of the aforementioned GSE-LLCdata, and/or a packet length element indicating a total length of thelink layer packet. The segment sequence element and the packet lengthelement have been described above in detail.

According to another embodiment of the present invention, theaforementioned total length of the link layer packet may indicate avalue obtained by adding a header length of the link layer packet and apayload length of the link layer packet, and when a payload includes asection table, the aforementioned length of the payload of the linklayer packet may indicate a length of a section table included in thepayload of the link layer packet. The aforementioned length of thesection table may indicate a value obtained by adding a value indicatedby the section_length_field at a position spaced apart from a start partof the section table by a predetermined offset, a length of thepredetermined offset, and a length of the section_length_field. Theaforementioned section_length_field may indicate a length to a last partof a corresponding section after the aforementionedsection_length_field. According to an embodiment of the presentinvention, the aforementioned predetermined offset may be 12 bits thatcorrespond to a value obtained by adding a table_id field length (8bits), a section_syntax_indicator field length (1 bit), a specific usefield length (1 bit), and a reserved field length (2 bit), which areincluded in the section table. The method for obtaining the length ofthe payload of the link layer packet has been described above in detail.

According to another embodiment of the present invention, theaforementioned payload of the link layer packet may include a fastinformation table or fast information descriptor including signalinginformation for rapid service scan and acquisition. The aforementionedfast information table and fast information descriptor have beendescribed above in detail.

FIG. 47 is a diagram illustrating a header of a link layer packet forrobust header compression (RoHC) transmission according to an embodimentof the present invention.

In an IP-based broadcast environment, an IP packet may also beencapsulated and transmitted as the aforementioned link layer packet.When streaming is performed in the IP-based broadcast system, headerinformation of the IP packet may be barely changed and may bemaintained. Based on this point, the header of the IP packet may beencapsulated.

An RoHC scheme may be mainly used to encapsulate a header (=IP header)of an IP packet. The present invention proposes an encapsulation methodwhen an RoHC packet is input to a link layer.

When the RoHC packet is input to a link layer, a value of theaforementioned packet type element may be 010_(B). As described above,the value may indicate that a packet transmitted to a link layer from ahigher layer is a compressed IP packet.

When the RoHC packet is input, a header of the link layer packet mayinclude a fixed header and/or an extended header like the otheraforementioned packets.

The fixed header may include a packet type field and/or a packetconfiguration (PC) field. The fixed header may have a total size of 1byte. Here, the packet type field may have a value of 010 in the case ofthe compressed IP packet. The extended header may have a variable orfixed size in some embodiments.

The PC field of the fixed header may indicate a form in which an Rol-ICpacket included in a payload of a link layer packet is processed.According to a value of the PC field, the remaining part of a fixedheader subsequent to the PC field and information of the extended headermay be determined. In addition, the PC field may contain lengthinformation of an extended header according to a form in which the RoHCpacket is processed. The PC field may have a size of 1 bit.

A case in which a value of the PC field is 0_(B) will now be described.

When the PC field has a value 0_(B), the payload of the link layerpacket includes one RoHC packet or two or more RoHC packets areconcatenated. Concatenation may refer to the case in which packets witha short length are connected to configure a payload of a link layerpacket.

When a value of the PC field is 0_(B), a common CID indicator (CI) fieldof 1 bit and a count field of 3 bits may be subsequent to the PC field.Accordingly, the common CID information and a length part may be addedto the extended header. The length part may indicate a length of an RoHCpacket.

The common CID indicator (CI) field may be set to 1 when context IDs(CIDs) of RoHC packets included in a payload of one link layer packetare the same, and otherwise, the CI field may be set to 0. When the CIvalue is 1, an overhead processing method for a common CID may beapplied. The CI field may be 1 bit.

The count field may indicate the number of RoHC packets included in apayload of one link layer packet. That is, with regard to concatenation,the number of concatenated RoHC packets may be indicated by the countfield. The count field may be 3 bits. Accordingly, as shown in thefollowing table, a maximum of 8 RoHC packets may be included in apayload of one link layer packet. When the count field has a value of000, the value may indicate that RoHC packets are not concatenated andone RoHC packet is included in a payload of a link layer packet.

TABLE 1 Count (3 bits) No. of Concatenated RoHC packets 000 1 001 2 0103 011 4 100 5 101 6 110 7 111 8

As described above, the length part may indicate a length of the RoHCpacket. In the case of the RoHC packet, length information is deletedfrom a header of the RoHC packet. Accordingly, a length field in theheader of the RoHC packet cannot be used. Accordingly, the header of thelink layer packet may include a length part such that a receiverrecognizes a length of a corresponding RoHC packet.

When a maximum transmission unit (MTU) is not determined, an IP packetmay have a maximum length of 65535 bytes. Accordingly, lengthinformation of 2 bytes is required in order to support an RoHC packet upto a maximum length. In addition, when a plurality of RoHC packets isconcatenated, a length field may be added by as much as the numberdetermined by the count field. In this case, the length part may includea plurality of length fields. However, when one RoHC packet is includedin a payload, the length part may include only one length field. Lengthfields may be arranged in the same way as an order of RoHC packetsincluded in a payload of a link layer packet. Each length field may havea byte value.

A common CID field may be a field in which a common CID is transmitted.A header part of the RoHC packet may include a context ID (CID) forchecking a relationship between compressed headers. The CID may maintainthe same value in a stable link state. Accordingly, RoHC packetsincluded in the payload of one link layer packet may include the sameCID. In this case, in order to reduce overhead, CID may be deleted fromthe header part of the RoHC packet included in concatenated payload, anda value of the common CID field may be indicated in a header of the linklayer packet. A receiver may recombine CIDs of the RoHC packet using thecommon CID field. When there is a common CID field, a value of theaforementioned CI field needs to be 1.

The case in which a value of the PC field 1_(B) will now be described.

When the value of the PC field is 1_(B), a payload of a link layerpacket includes segmented packets of an RoHC packet. Here, the segmentedpacket may refer to the case in which an RoHC packet with a long lengthis segmented into a plurality of segments and one of the segments isincluded in a payload of a link layer packet.

When a value of the PC field is 1_(B), a last segment indicator (LI) of1 byte and a segment ID field of 3 bits may be subsequent to the PCfield. In addition, in order to add information about segmentation, asegment sequence number field, a segment length ID field, a last segmentlength field, and so on may be added to an extended header.

A last segment indicator (LI) field may be used when an RoHC packet issegmented. The RoHC packet may be segmented into a plurality ofsegments. When an LI value is 1, the value may indicate that a segmentincluded in a current link layer packet is a segment that is lastlypositioned among segments segmented from one RoHC packet. When an LIvalue is 0, the value may indicate that a segment included in a currentlink layer packet is not a last segment. The LI field may be used todetermine whether all segments are received when the receiver collectssegments to reconfigure one RoHC packet. The LI field may be 1 bit.

A segment ID (Seg_ID) field may indicate an ID provided to an RoHCpacket when an RoHC packet is segmented. Segments from one RoHC packetmay have a segment ID of the same value. When transmitted segments arecombined into one segment, the receiver may determine whether componentsare from the same RoHC packet using a segment ID. The segment ID fieldmay be 3 bits. Accordingly, segmentation of 8 RoHC packets may besimultaneously supported.

A segment sequence number (Seg_SN) field may be used to check a sequenceof each segment when an RoHC packet is segmented. That is, link layerpackets having segments from one RoHC packet as a payload may have thesame Seg_ID but have different Seg_SNs. The Seg_SN may be 4 bits.Accordingly, one RoHC packet may be segmented into a maximum of 16segments.

A segment length ID (Seg_Len_ID) field may be used to indicate eachsegment length. However, the segment length ID field may be used toindicate a length of a segment except for a last segment among aplurality of segments. The length of the last segment may be indicatedby a length field of a last segment, which will be described below. Whena payload of a link layer packet is not a last segment of an RoHCpacket, that is, when a value of LI is 0, a segment length ID field maybe present.

In order to reduce overhead of a header, a length of a segment may belimited to 16. An input size of a packet may be determined according toa code rate of FEC processed in a physical layer. A length of a segmentmay be determined according to the input size and determined as theSeg_Len_ID. When a physical layer is operated irrespective of a segmentlength, the length of the segment may be determined as follows.Segment Length=Seg_Len_ID×Len_Unit+min_Len [bytes]  [Equation 1]

Here, a length unit (Len_Unit) may be a basic unit indicating a lengthof a segment and min_Len may refer to a minimum of a segment length. TheLen_Unit and the min_Len may have the same value in a transmitter and areceiver and it is effective in terms of system management when theLen_Unit and the min_Len are not changed after being determined once. Inaddition, the Len_Unit and the min_Len may be determined inconsideration of processing capability of FEC of a physical layer duringan initialization procedure of a system.

The following table summarizes a length of a segment, which isrepresented according to a Seg_Len_ID, and an exemplary length allocatedto the Seg_Len_ID may be changed according to a designer's intention.According to the present embodiment, a value of the Len_Unit may be 256and a value of the min_Len may be 512.

TABLE 2 Seg_Len_ID Segment Length (byte) 0000 512 (=min_Len) 0001  7680010 1024 0011 1280 0100 1536 0101 1792 0110 2048 0111 2304 1000 25601001 2816 1010 3072 1011 3328 1100 3584 1101 3840 1110 4096 1111 4352

A last segment length (L_Seg_Len) field may be used when a segmentincluded in a payload of a link layer packet is a last segment of theRoHC packet. That is, when a value of the LI field is 1, the lastsegment length (L_Seg_Len) field may be used. An RoHC packet may besegmented with the same size from a front part using the Seg_Len_ID.However, in this case, a last segment may not be segmented to a sizeindicated by the Seg_Len_ID. Accordingly, a length of a last segment maybe directly indicated by the L_Seg_Len field. The L_Seg_Len field mayindicate 1 to 4095 bytes, which can be changed in some embodiments.

FIG. 48 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet according to Embodiment #1 of thepresent invention.

The present embodiment may correspond to the case in which one RoHCpacket is included in a payload of a link layer packet when the RoHCpacket is within a processing range of a physical layer. In this case,the RoHC packet may not be concatenated or segmented.

In this case, one RoHC packet may be a payload of a link layer packetwithout change. A value of the packet type may be 010_(B), a value ofthe PC field may be 0_(B), and a value of a CI field may be 0_(B). Inthe case of the aforementioned count field, since one RoHC packet isincluded in a (single) payload without change, the RoHC packet may havea value of 000_(B) as described above. Then a length field of 2 bytesindicating a length of the RoHC packet may be subsequent to the RoHCpacket. In this case, since only one packet is included in a payload, alength part may include only one length field.

According to the present embodiment, a total of 3 bytes of a link layerheader may be added. Accordingly, when a length of an RoHC packetindicated by the length field is L bytes, a total length of the linklayer packet may be (L+3) bytes.

FIG. 49 is a diagram of a method for transmitting an RoHC packet througha link layer packet according to Embodiment #2 of the present invention.

According to the present embodiment, since the RoHC packet does notreach a processing range of a physical layer, a plurality of RoHCpackets is concatenated and are included in a payload of a link layerpacket (concatenation).

In this case values of the PC field and the CI field may be the same asin a case in which one RoHC packet is included in a payload. A countfield is subsequent to the PC field and the CI field. The count fieldmay have a value of 001_(B) to 111_(B) according to the number of RoHCpackets included in a payload, as described above.

Then length fields with a length of 2 bytes may be positioned subsequentto the count field by as much as the number indicated by the countfield. The length field may be referred to as a length part.

Here, when a value indicated by the count field is n, RoHC packets R₁,R₂, . . . , R_(n) with a length of L₁, L₂, . . . , L_(n), may beconcatenated in a payload of a link layer packet.

A total extended header may have a length of 2n bytes. A total lengthL_(T) of a link layer packet may be represented according to thefollowing equation.

$\begin{matrix}{L_{T} = {1 + {2\; n} + {\sum\limits_{k = 1}^{n}\;{L_{k}\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

FIG. 50 is a diagram illustrating a method for transmitting an RoHCpacket of a link layer packet according to Embodiment #3 of the presentinvention.

According to the present embodiment, when a plurality of RoHC packets isconcatenated to configure a payload of a link layer packet, theconcatenated RoHC packets have the same context ID (CID).

When the RoHC packets have the same CID, even if the CID is marked andtransmitted once, a receiver may restore an RoHC packet and a headerthereof to an original state. Accordingly, a CID common to RoHC packetsmay be extracted and transmitted once, and in this case, overhead may bereduced.

In this case, a value of the aforementioned CI field may be 1. Thismeans that processing is performed on the same CID. RoHC packets havingthe same CID may be represented by [R1, R2, R3, . . . , Rn]. The commonCID may be referred to as Common CID. A packet obtained by excluding aCID from a header of an RoHC packet may be denoted by R′k (k is 1, 2, .. . , n).

A payload of a link layer packet may include R′k (k is, 2, . . . , n). Acommon CID field may be added to a last part of an extended header of alink layer packet. The common CID field may be a field in which a commonCID is transmitted. The common CID field may be transmitted to one partof the extended header or transmitted to one part of the payload of thelink layer packet. According to system management, the common CID fieldmay be appropriately reordered at a position at which a position of thecommon CID field can be checked.

A size of the common CID field may be changed according to aconfiguration of the RoHC packet.

When the configuration of the RoHC packet is a small CID configuration,a size of a CID of the RoHC packet may be 4 bits. However, when a CID isextracted from the RoHC packet and reordered, an add-CID octet may beentirely processed. That is, the common CID field may have a length of 1byte. Alternatively, an add-CID octet of 12 byte may be extracted fromthe RoHC packet, only a CID of 4 bits may be allocated to a common CIDfield, and the remaining 4 bits may be reserved for future use.

When a configuration of the RoHC packet is a large CID configuration, aCID size of the RoHC packet may have a length of 1 byte or 2 bytes. Thesize of the CID may be determined during an RoHC initializationprocedure. According to the size of the CID, the common CID field mayhave a length of 1 byte or 2 bytes.

According to the present embodiment, a length of a payload of a linklayer packet may be calculated as follows. Lengths of n RoHC packets R₁,R₂, . . . , R_(n) having the same CID may be referred to as L₁, L₂, . .. , L_(n), respectively. When a length of a header of a link layerpacket is L_(H), a length of a common CID field is L_(CID), and a totallength of a link layer packet is L_(T), L_(H) may be represented asfollows.L _(H)=1+2n+L _(CID) bytes  [Equation 3]

In addition, L_(T) may be calculated as follows.

$\begin{matrix}{L_{T} = {L_{H} + {\sum\limits_{k = 1}^{n}{\left( {L_{k} - L_{CID}} \right)\mspace{14mu}{bytes}}}}} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack\end{matrix}$

As described above, L_(CID) may be determined according to a CIDconfiguration of RoHC. That is, in the case of a small CIDconfiguration, L_(op) may be 1 byte, and in the case of a large CIDconfiguration, L_(CID) may be 1 byte or 2 bytes.

FIG. 51 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet according to Embodiment #4 of thepresent invention.

According to the present embodiment, when an input RoHC packet exceeds aprocessing range of a physical layer (segmentation), segmented segmentsmay each be encapsulated into a payload of a link layer packet.

In order to indicate that a payload of a link layer packet includessegmented RoHC packets, a value of the PC field may be 1_(B). A value ofthe LI field may be 1_(B) only when a segment corresponding to a lastpart of the RoHC packet is a payload, and a value of the LI field may be0_(B) with respect to all remaining segments. A value of the LI fieldmay indicate information about an extended header of a link layerpacket. That is, when a value of the LI field is 0_(B), an extendedheader with a length of 1 byte may be added, and when a value of the L1field is 1_(B), an extended header with a length of 2 bytes may beadded.

In order to indicate that segments are segmented from the same RoHCpacket, the Seg_ID needs to have the same value. In order to indicate asequence order of segments for recombination of normal RoHC packets, areceiver may record a value of the Seg_SN, which is sequentiallyincreased, in a header.

During segmentation of the RoHC packet, a length of a segment may bedetermined to perform segmentation, as described above. A value of theSeg_Len_ID according to the length may be recorded in the header. Asdescribed above, the length of the last segment may be recorded directlyin an L_Seg_Len field of 12 bits.

Length information indicated using the Seg_Len_ID and the L_Seg_Lenfield may indicate only information about a segment, that is, a payloadof a link layer packet. Accordingly, total length information of a linklayer packet may be calculated by adding header lengths of the linklayer packet, which are known through the LI field.

During recombination of segments of an RoHC packet, a receiving sideneeds to check integrity of the recombined RoHC packet. To this end, CRCmay be added behind the IP packet during the segmentation procedure. Ingeneral, the CRC is added to a last part of the RoHC packet, and thusthe CRC may be included in the last segment after the segmentationprocedure.

FIG. 52 is a diagram illustrating a header of a link layer packet forRoHC transmission when MTU is 1500, according to an embodiment of thepresent invention.

In general, an RoHC scheme may be applied during video and audiostreaming. In this case, a maximum transmission unit (MTU) of the IPpacket may be set to 1500 bytes. This means that the RoHC packet alsohas a shorter length than 1500 bytes.

As described above, a PC field of the fixed header may indicate a formin which an RoHC packet included in a payload of a link layer packet isprocessed. According to a value of the PC field, information about theremaining part of the fixed header and the extended header, subsequentto the PC field, may be determined. In addition, the PC field mayinclude length information of an extended header according to the formin which the RoHC packet is processed. The PC field may have a size of 1bit.

The case in which a value of the PC field is 0_(B) will now bedescribed.

When the value of the PC field is 0_(B), a payload of a link layerpacket includes one RoHC packet or includes segmented packets of theRoHC packet. An SI field may be subsequent to the PC field. The segmentindicator (SI) may indicate whether the payload of the link layer packetincludes one RoHC packet or segments of the RoHC packet. According to avalue of the SI field, fields of the fixed header and extended headerparts may be determined.

As described above, the SI field may indicate whether the payload of thelink layer packet includes one RoHC packet or includes segments of theRoHC packet. In the case of a value of 0, the value may mean that thepayload includes one RoHC packet, and in the case of 1, the value maymean that the payload includes segments of the RoHC packet. The SI fieldmay be 1 byte.

A segment ID (Seg_ID) field may indicate an ID provided to an RoHCpacket when the RoHC packet is segmented. This is the same as theaforementioned Seg_ID field.

The segment sequence number (Seg_SN) field may be used to check asequence of each segment when the RoHC packet is segmented. This is thesame as the aforementioned Seg_SN field.

The last segment indicator (LI) field may indicate whether a segmentincluded in a current link layer packet is a lastly positioned segmentamong segments segmented from the RoHC packet when the RoHC packet issegmented. This is the same as the aforementioned LI field.

A segment length ID (Seg_Len_ID) field may be used to indicate a lengthof each segment. This is the same as the aforementioned Seg_Len_IDfield. However, unlike in the aforementioned case, the number of lengthsof the segment may be limited to 8 instead of 16. In this case, a lengthof the segment represented according to a value of the Seg_Len_ID may besummarized according to the following table. A length allocated to theSeg_Len_ID is an embodiment and may be changed according to a designer'sintention. According the present embodiment, the Len_Unit may have avalue of 64 and the min_Len may have a value of 256.

TABLE 3 Seg_Len_ID Segment Length (byte) 000 256 (=min_Len) 001 320 010384 011 448 100 512 101 576 110 640 111 704

The last segment length (L_Seg_Len) field may be used to represent alength of a last segment. This is the same as the aforementionedL_Seg_Len field. However, unlike in the aforementioned case, theL_Seg_Len field may be represented by 1 to 2048 bytes. This may bemodified in some embodiments.

The case in which a value of the PC field is 1_(B) will now bedescribed.

When the value of the PC field is 1_(B),

two or more RoHC packets are concatenated in a payload of a link layerpacket. A common CID indicator (CI) field of 1 byte and a count field of3 bits may be subsequent to the PC field. Accordingly, common CIDinformation and a length part may be added to the extended header.

The common context ID indictor (CI) field may indicate whether contextIDs (CIDs) of RoHC packets included in a payload of one link layerpacket are the same. The CI field is the same as in the aforementionedcase.

The count field may indicate the number of RoHC packets included in apayload of one link layer packet. Unlike in the aforementioned countfield, a value 000 may be allocated to indicate that two RoHC packetsare concatenated. When a value of the count field is 111, the value mayindicate that 9 or more RoHC packets are concatenated. This may besummarized according to the following table.

TABLE 4 No. of Concatenated RoHC packets Count (3 bits) (MTU = 1500bytes) 000 2 001 3 010 4 011 5 100 6 101 7 110 8 111 9 or more packets,Extended length field is used

The length part may indicate a length of an RoHC packet. The length partmay include a plurality of length fields as described above. Each lengthfield may indicate a length of each RoHC packet.

According to the present embodiment, the MTU may be 1500 bytes, and thusthe length field may be allocated 11 bits as a minimum bit number inorder to indicate that the MTU is 1500 bytes. Since up to 2048 bytes canbe indicated by 11 bits, and thus when the MTU is extended to 2048 bytesfor future use, the method proposed by the present invention may beused. The length field may directly indicate a length thereof or mayindicate the length by mapping with a separate value. As describedabove, the length field may be added by the number determined by thecounted field.

When the number of concatenated RoHC packets is 9 or more, the extendedlength part may be used to indicate a length of an RoHC packet after a9^(th) RoHC packet. That is, the extended length part may be used when avalue of the count field is 111_(B). The extended length part mayinclude a length field of 11 bits and an X field of 1 bit. The twofields may be alternately positioned.

The common CID field may be a field in which a common CID istransmitted. This may be the same as in the aforementioned common CIDfield.

FIG. 53 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #1 of the present invention.

According to the present embodiment, when the MTU is 1500, a PC fieldmay be 1 and a count value may not be 111_(B).

In this case, the length part may have length fields, the number ofwhich corresponds to the number determined by the count field value, asdescribed above. One length field is 11 bits, and thus a padding bit maybe added according to the number of length fields. That is, when anumber determined by the count field is k and a size of one length fieldis s (bits), a total length L_(LP) of a length part may be calculated asfollows.

$\begin{matrix}{L_{LP} = {\left\lceil \frac{k \times s}{8} \right\rceil\mspace{14mu}\lbrack{Bytes}\rbrack}} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

In addition, a size of the padding bit added to the length part may becalculated as follows.L _(padding)=(8×L _(LP))(k×s) [Bits]  [Equation 6]

As described above, a length s of the length field may be 11 bits. Basedthereon, sizes of the length part and padding bit may be summarized asfollows.

TABLE 5 No. of Concatenated Count RoHC packets Size of Length Size of (3bits) (MTU = 1500 bytes) Part (Bytes) Padding (bits) 000 2 3 2 001 3 5 7010 4 6 4 011 5 7 1 100 6 9 6 101 7 10 3 110 8 11 1

FIG. 54 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #2 of the present invention.

According to the present embodiment, when the MTU is 1500, a PC field is1 and a count value is 111_(B). In this case, as described above, anextended length part may be added.

In this case, a length part in front of the extended length partincludes 8 length fields of 11 bits, and thus the length part may have atotal length of 11 bytes. The count value is 111, and thus at least onelength field needs to exist in the extended length part.

As described above, the extended length part may include a length fieldof 11 bits and an X field of 1 bit. The two fields may be alternatelypositioned. The length part of the extended length part may be managedin the same way as the length field of the length part.

The X field may indicate whether a length field is further subsequent tothe X field. When a value of the X field is 0, the value may mean that alength field is not added any longer. When a value of the X field is 1,the value may mean that at least one length field and X field aresubsequent to the corresponding field. Accordingly, until a value of theX field is 0, the extended length part may be continuously increased.The number of RoHC packets positioned in a payload is added by thenumber of X fields.

In the extended length part, when the number of X fields with a value 1is m and a size of one length field is s (bits), a length L_(ELP) of theextended length part may be calculated as follows.

$\begin{matrix}{L_{ELP} = {\left\lceil \frac{\left( {m + 1} \right) \times \left( {s + 1} \right)}{8} \right\rceil\mspace{14mu}\lbrack{Bytes}\rbrack}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

The extended length part may also have padding bits for processing of abyte unit. A size of the padding bit added to the extended length partmay be calculated as follows.L _(E_padding)=(8×L _(ELP))−((m+1)×(s+1)) [Bits]  [Equation 8]

When the number of length fields is an odd number, 4 padding bits may beadded, and when the number of length fields is an even number, a paddingbit may not be added.

FIG. 55 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #3 of the present invention.

According to the present embodiment, when the MTU is 1500, an RoHCpacket is within a processing range of a physical layer, and thus oneRoHC packet is included in a payload of a link layer packet.

In this case, one RoHC packet may be a payload of a link layer packetwithout change. A value of a packet type may be 010_(B), a value of thePC field may be 0_(B), and a value of the SI field may be 0_(B). Theaforementioned length part may be subsequent thereto. Here, the lengthpart may have one length field. The length field may be 11 bits. For 11bits, 3 bits of a fixed header and 1 byte of an extended header may beused for one length field.

In this case, a link layer header having 2 bytes in total isadditionally provided. Accordingly, when a length of an RoHC packet,indicated by the length field, is L bytes, a total length of the linklayer packet is (L+2) bytes.

FIG. 56 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #4 of the present invention.

According to the present embodiment, when the MTU is 1500, an input RoHCpacket exceeds a processing range of a physical layer (segmentation),and thus the segmented segments are encapsulated into a payload of alink layer packet.

In order to indicate segmentation, a value of the SI field may be 1.

As described above, the Seg_ID needs to have the same value and theSeg_SN needs to have a value that is sequentially increased. The LIfield may have a value of 1 only in the case of a last segment and mayhave a value of 0 in the remaining cases. In addition, a length of eachsegment may be indicated using the Seg_Len_ID and L_Seg_Len fields. Adetailed method for indicating a length may be the same as in theaforementioned case.

Total length information of a link layer packet may be calculated byadding a header length of a link layer packet, which can be knownthrough the LI field. In addition, in order to check integrity during aprocedure for recombining segments of an RoHC packet, a receiving sidemay add CRC. The CRC may be added to a last segment.

FIG. 57 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #5 of the present invention.

According to the present embodiment, when the MTU is 1500, an RoHCpacket does not reach a processing range of a physical layer, and aplurality of RoHC packets is concatenated and included in a payload of alink layer packet (concatenation).

According to the present embodiment, 8 or fewer RoHC packets may beconcatenated. In this case, an extended length part may not be required.A value of the PC field may be 1 and a value of the CI field may be 0.As described above, a value of the count field may be 000_(B) to110_(B).

Here, when a value indicated by the count field is n, RoHC packets R₁,R₂, . . . , R_(n), with lengths L₁, L₂, . . . , L_(n), may beconcatenated in a payload of a link layer packet. Each length field mayhave a length of 11 bits. As necessary, a padding bit may be positionedsubsequent to the length field.

A total length L_(T) of a link layer packet may be represented asfollows

$\begin{matrix}{L_{T} = {1 + L_{LP} + {\sum\limits_{k = 1}^{n}{L_{k}\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

Here, L_(LP) may be a total length of a length part and L_(k) may be alength of each RoHC packet.

FIG. 58 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MUT is 1500 according toEmbodiment #6 of the present invention.

According to the present embodiment, when the MTU is 1500, the RoHCpacket does not reach a processing range of a physical layer, and aplurality of RoHC packets is concatenated and included in a payload of alink layer packet (concatenation).

However, according to the present embodiment, 9 or more RoHC packets maybe concatenated. In this case, an extended length part other than thelength part may be required. As described above, the count field mayhave a value of 111.

In an extended length part, when the number of X fields with a value of1 is m, the number n of RoHC packets concatenated in a payload of thelink layer packet may be 8+(m+1). In this case, a total length L_(T) ofthe link layer packet may be represented as follows.

$\begin{matrix}{L_{T} = {1 + L_{LP} + L_{ELP} + {\sum\limits_{k = 1}^{n}{L_{k}\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 10} \right\rbrack\end{matrix}$

Here, L_(LP) may be a total length of the length part and L_(k) may be alength of each RoHC packet. Here, L_(ETp) may be a total length of theextended length part.

FIG. 59 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when an MTU is 1500 according toEmbodiment #7 of the present invention.

According to the present embodiment, the MTU is 1500, a plurality ofRoHC packets is concatenated and included in a payload of a link layerpacket. However, according to the present embodiment, concatenated RoHCpackets may have the same context ID (CID).

In this case, a value of the aforementioned CI field may be 1. This maymean that processing is performed on the same CID. RoHC packets havingthe same CID are represented by [R1, R2, R3, . . . , Rn]. A CID commonto the RoHC packets may be referred to as a common CID. A packet exceptfor a CID from a header of an RoHC packet may be represented by R′k (kis 1, 2, . . . , n).

A payload of a link layer packet may include R′k (k is 1, 2, . . . , n).A common CID field may be a field in which a common CID is transmitted.The common CID field may be transmitted in one part of the extendedheader or transmitted in one part of a payload of a link layer packet.According to system management, the common CID field may beappropriately rearranged at a position at which a position of the commonCID field can be checked.

A size of the common CID field may be varied according to aconfiguration of an RoHC packet.

When a configuration of an RoHC packet is a small CID configuration, asize of a CID of the RoHC packet may be 4 bits. However, when the CID isextracted and reordered in the RoHC packet, all add-CID octets may beprocessed. That is, a common CID field may have a length of 1 byte. Inaddition, after an add-CID octet of 1 byte is extracted from an RoHCpacket, only a CID of 4 bits is allocated to the common CID field, andthen the remaining 4 bits may be reserved for future use.

When a configuration of an RoHC packet is a large CID configuration, asize of a CID of an RoHC packet may be a length of 1 byte or 2 bytes. Asize of the CID may be determined in an RoHC initialization procedure.According to the size of the CID, the common CID field may have a lengthof 1 byte or 2 bytes.

In this case, a total length L_(T) of a link layer packet may becalculated as follows.

$\begin{matrix}{L_{T} = {1 + L_{LP} + L_{CID} + {\sum\limits_{k = 1}^{n}{\left( {L_{k} - L_{CID}} \right)\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 11} \right\rbrack\end{matrix}$

Here, L_(CID) may refer to a length of a common CID field. As describedabove, L_(CID) may be determined according to the CID configuration ofthe RoHC.

Using the same method, when n is 9 or more (when a value of the countfield is 111_(B)), a total length L_(T) of the link layer packet may becalculated as follows.

$\begin{matrix}{L_{T} = {1 + L_{LP} + L_{ELP} + L_{CID} + {\sum\limits_{k = 1}^{n}{\left( {L_{k} - L_{CID}} \right)\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 12} \right\rbrack\end{matrix}$

Similarly, here, L_(CID) may refer to a length of a common CID field.

FIG. 60 is a diagram illustrating a configuration of a header of a linklayer packet when an IP packet is transmitted to a link layer, accordingto another embodiment of the present invention.

In this case, the header of the link layer packet may include a fixedheader and an extended header. The fixed header may have a length of 1byte and the extended header may have a fixed length or a variablelength. A length of each header may be changed according to a designer'sintention.

The fixed header may include a packet type field, a PC field, and/or acount field. According to another embodiment of the present invention,the fixed header may include a packet type field, a PC field, an LIfield, and/or a segment ID field.

The extended header may include a segment sequence number field and/or asegment length ID field. According to another embodiment of the presentinvention, the extended header may include a segment sequence numberfield and/or a last segment length field.

Fields of the fixed header will be described below.

As described above, the packet type field may indicate a type of apacket input to a link layer. When the IP packet is input to the linklayer, a value of the packet type field may be 000B or 001B.

A packet configuration (PC) field may indicate the remaining part of asubsequent fixed header and/or a configuration of the extended header.That is, the PC field may indicate a type of an input IP packet.Accordingly, the PC field may contain information about a length of theextended header.

When a value of the PC field is 0, this may mean that a payload of alink layer packet includes one IP packet or two or more concatenated IPpackets. Here, concatenation may indicate that a plurality of packetswith a short length is connected to configure a payload.

In addition, when a value of the PC field is 0, a count field of 4 bitsmay be subsequent to the PC field. Here, the count field may indicatethe number of concatenated IP packets included in one payload. Thenumber of concatenated IP packets according to a value of the countfield will be described below.

In addition, when a value of the PC field is 0, a link layer may notinclude an extended header. However, in some embodiments, when a lengthof a link layer packet needs to be indicated, an extended header of 1-2bytes may be added. In this case, the extended header may be used toindicate the length of the link layer packet.

When a value of the PC field is 1, this may mean that a payload of alink layer packet includes segmented packets. Here, the segmented packetmay indicate the number of segments segmented from an IP packet with along length. Each segmented segment may be referred to as a segment or asegmented packet. That is, when a value of the PC field is 1, thepayload of the link layer packet may include one segmented packet, thatis, a segment.

When a value of the PC field is 1, an LI field of 1 bit and a segment IDfield of 3 bits may be subsequent to the PC field.

A last segment indicator (LI) field may indicate whether a correspondinglink layer packet includes a last segment among segmented segments. Thatis, when a value of LI field is 1, a corresponding link layer mayinclude a very last segment among segmented segments, and when a valueof the LI field is 0, the corresponding link layer may not include thevery last segment. The LI field may be used to reconfigure an originalIP packet by a receiver. A value of the LI field may indicateinformation about an extended header of a link layer packet. That is,when a value of the LI field is 0, a length of the extended header maybe 1 byte, and when the value is 1, the length of the extended headermay be 2 bytes, which will be described below in detail.

The segment ID field may indicate an ID of a segment included in acorresponding link layer packet. When one IP packet is segmented,segments may be provided with the same ID. The segment ID may indicatethat segments are components of the same IP packet when the receiverreconfigures an original IP packet. The segment ID field has a size of 3bits, and thus segmentation of a total of 8 IP packets may besimultaneously supported.

In addition, when a value of the PC field is 1, an extended header maybe used for information about segmentation. As described above, theextended header may include a segment sequence number, a segment lengthID field, and/or a last segment length field, etc.

Fields of the extended header will now be described.

When the aforementioned LI field has a value of 0, that is, when asegment included in a link layer packet is not a last segment, theextended header may include a segment sequence number field and/or asegment length ID field.

The segment sequence number field may include a sequencer of a segmentedpacket. Accordingly, link layer packets having segments segmented fromone IP packet may have the same segment ID field but have differentsegment sequence number fields. The segment sequence number field has asize of 4 bits, and thus one IP packet may be segmented into a maximumof 16 segments.

The segment length ID field may indicate lengths of segments that arenot a last segment. The lengths of the segments that are not a lastsegment may be the same. Accordingly, the lengths thereof may berepresented using a predetermined length ID. The segment length ID fieldmay indicate a length ID thereof.

A length of a segment may be set according to an input size of a packet,which is determined according to an FEC code rate of a physical layer.That is, the length of the segment may be determined according to theinput size thereof, and the segments thereof may be determined by asegment length ID. In order to reduce overhead of a header, a length ofa segment may be limited to 16.

A value of a segment length ID field according to a length of a segmentwill be described later.

When a physical layer operates irrespective of a length of a segment,the length of the segment may be obtained by adding a minimum segmentlength (min_Len) to a product of a segment length ID and a length unit(Len_Unit). Here, the Len_Unit may be a basic unit indicating a lengthof a segment and the min_Len may refer to a minimum segment length. TheLen_Unit and the min_Len may always have the same value in a transmitterand a receiver, and it is effective in terms of system management whenthe Len_Unit and the min_Len are not changed after being determinedonce. The Len_Unit and the min_Len may be determined in consideration ofprocessing capability of FEC of a physical layer during aninitialization procedure of a system.

When the aforementioned LI field has a value of 1, that is, when asegment included in a link layer packet is a last segment, an extendedheader may include a segment sequence number field and/or a last segmentlength field.

The segment sequence number field is the same as in the aforementionedcase.

The last segment length field may directly indicate a length of a lastsegment. When one IP packet is segmented into segments with a specificlength, the last segment may have a different length from othersegments. Accordingly, the last segment length field may directlyindicate a length of the last segment. The last segment length field mayindicate 1-4095 bytes. A byte number to be indicated may be different insome embodiments.

FIG. 61 is a diagram illustrating information indicated by each field ina header of a link layer packet when an IP packet is transmitted to alink layer, according to another embodiment of the present invention.

As described above, the number of concatenated IP packets may bedetermined according to a value of a count field (t61010). The value ofthe count field may refer to the number of concatenated IP packetswithout change but may be meaningless when 0 packets are concatenated.Accordingly, the count field may indicate that IP packets, the number ofwhich is obtained by adding 1 to the value of the count field, areconcatenated. That is, as shown in Table (t61010), 0010 may indicatethat 3 IP packets are concatenated and 0111 may indicate that 8 IPpackets are concatenated.

Here, when a value of the count field is 0000, the value may indicatethat one IP packet is concatenated and indicate that a payload of a linklayer packet includes one IP packet without concatenation.

As described above, a length of a segmented segment may be representedby a value of a segment length ID field (t61020).

For example, when a value of the segment length ID field is 0000, asegment length may be 512 bytes. This may indicate that a segmentincluded in a payload of a corresponding link layer packet is not a lastsegment and has a length of 512 bytes. When other segments segmentedfrom the same IP packet of the segment are not a last segment, thesegment may have a length of 512 bytes.

In the tables, a length unit may have a value of 256 and a minimumsegment length may have a length of 512. Accordingly, the minimumsegment length may be 512 bytes (segment length ID field=0000). Inaddition, determined lengths of a segment may be increased with aninterval of 256 bytes.

FIG. 62 is a diagram illustrating the case in which one IP packet isincluded in a link layer payload with respect to a header of a linklayer packet when an IP packet is transmitted to a link layer, accordingto another embodiment of the present invention.

When one IP packet is included in a link layer payload, the case inwhich concatenation or segmentation is not performed may be referred toas encapsulation into a normal packet. In this case, an IP packet may bewithin a processing range of a physical layer.

According to the present embodiment, a link layer packet may have aheader of a total of 1 byte. A length of the header may be changed insome embodiments. A value of the packet type field may be 000 (in thecase of IPv4) or 001 (in the case of IPv6). The normal packetencapsulation procedure may be applied to IPv4 or IPv6 in the same way.A value of the PC field may be 0 since one packet is included in apayload. A subsequent count field may have a value of 0000 since onlyone packet is included in a payload.

According to the present embodiment, a payload of a link layer packetmay include one IP packet without change.

According to the present embodiment, information of an IP packet headermay be used in order to check a length of a link layer packet. The IPpacket header may include a field indicating a length of an IP packet.The field may be referred to as a length field. A position of an IPpacket, in which the length field is positioned, may be fixed. Since oneIP packet is included in a payload of a link layer without change, thelength field may be positioned at a position spaced apart from aninitial part of the payload of the link layer packet by a predeterminedoffset length. Accordingly, a total length of the payload of the linklayer may be known using the length field.

In the case of IPv4, the length field may be positioned at a positionspaced apart from a start point of a payload by 2 bytes, and in the caseof IPv6, the length field may be positioned at a position spaced apartfrom the start point of the payload by 4 bytes. The length field mayhave a length of 2 bytes.

In the case of IPv4, when a value of the length field is LIPv4 and aheader length of the link layer packet is LH (1 byte), a total length LTof a link layer packet may be represented according to the shownequation (t62010). Here, a value LIPv4 of the length field may indicatea total length of an IPv4 packet.

In the case of IPv6, when a value of the length field is LIPv6 and aheader length of the link layer packet is LH (1 byte), a total length LTof a link layer packet may be represented according to the shownequation (t62020). Here, a value LIPv6 of the length field may indicateonly a length of a payload of an IPv6 packet, and thus a length (40bytes) of a fixed header of an IPv6 packet needs to be added in order toobtain the total length of the link layer packet.

FIG. 63 is a diagram illustrating the case in which a plurality of IPpackets is concatenated and included in a link layer payload withrespect to a header of a link layer packet when an IP packet istransmitted to a link layer, according to another embodiment of thepresent invention.

When an input IP packet does not reach a processing range of a physicallayer, a plurality of IP packets may be concatenated and encapsulatedinto a payload of one link layer packet.

According to the present embodiment, a link layer packet may have aheader with a total of 1 byte. A length of the header may be changed insome embodiments. A value of the packet type field may be 000 (in thecase of IPv4) or 001 (in the case of IPv6). An encapsulation procedureaccording to the present embodiment may be applied to IPv4 or IPv6 inthe same way. A value of the PC field may be 0 since a plurality ofconcatenated IP packets is included in a payload. A subsequent countfield may indicate the number of concatenated IP packets (4 bits).

According to the present embodiment, a payload of a link layer packetmay include a plurality of IP packets. The IP packets may beconcatenated by connecting front and rear parts thereof and included ina payload of a link layer packet. A concatenation method may be changedaccording to designer intention.

According to the present embodiment, in order to check a length of alink layer packet, information of a header of a concatenated IP packetmay be used. Like the aforementioned normal packet encapsulation, alength field indicating a length of an IP packet may exist in a headerof the IP packet. In addition, the length fields may be positioned at afixed position in the IP packet.

Accordingly, when a header length of a link layer packet is LH and alength of each IP packet is Lk (here, k is equal to or more than 1 andis equal to or less than n), a total length LT of a link layer packetmay be represented according to the shown equation (t63010). That is,when a header length of a link layer packet is added to a value obtainedby summing lengths of IP packets indicated by length fields of IPpackets, a total length of the link layer packet may be obtained. Avalue of Lk may be checked by reading a length field of a header of eachIP packet.

FIG. 64 is a diagram illustrating the case in which one IP packet issegmented and included in a link layer payload with respect to a headerof a link layer packet when an IP packet is transmitted to a link layer,according to another embodiment of the present invention.

When an input IP packet exceeds a processing range of a physical layer,one IP packet may be segmented into a plurality of segments. Thesegmented segments may be encapsulated into a payload of each link layerpacket.

According to the present embodiment, link layer packets t64010, t64020,and t64030 may each have a fixed header and an extended header. Lengthsof the fixed header and the extended header may be changed in someembodiments. A value of a packet type field may be 000 (in the case ofIPv4) or 001 (in the case of IPv6). An encapsulation procedure accordingto the present embodiment may be applied to IPv4 or IPv6 in the sameway. A value of the PC field may be 1 since segmented segments areincluded in a payload.

The link layer packets t64010 and t64020 having segments that are not alast segment as a payload may have an LI field value of 0 and thesegment ID fields may have the same value. This is because the segmentsare segmented from the same IP packet. A subsequent segment sequencenumber field may indicate a sequence of a corresponding segment. Here, asegment sequence field value of the first link layer packet t64010 mayindicate that a corresponding link layer packet has a first segment as apayload. A segment sequence field value of the second link layer packett64020 may indicate that a corresponding link layer packet has a secondsegment as a payload. The segment length ID field may represent a lengthof a segmented segment with a predetermined length ID.

The link layer packet t64030 having a last segment as a payload may havean LI field value of 1. Here, the segment ID field may be the same asother link layer packets. This is because a last segment is alsosegmented from the same IP packet. A subsequent segment sequence numberfield may indicate a sequence of a corresponding segment. A last segmentlength field may directly indicate a length of a last segment of thelink layer packet t64030.

According to the present embodiment, in order to check a length of alink layer packet, a segment length ID field or a last segment lengthfield may be used. The respective fields indicate only a length of apayload of a corresponding link layer packet, and thus a header lengthof a link layer packet needs to be added in order to obtain a totallength of the link layer packet. The header length of the link layerpacket may be known from the LI field, as described above.

FIG. 65 is a diagram illustrating link layer packets having segmentedsegments with respect to a header of a link layer packet when an IPpacket is transmitted to a link layer, according to another embodimentof the present invention.

According to the present embodiment, it is assumed that an IP packet of5500 bytes is input. Since a value obtained by dividing 5500 by 5 is1100, each segment may be configured with a length of 1024 bytes closestto the value. In this case, a last segment may be 1404 bytes(010101111100B). Segmented segments may be referred to as S1, S2, S3,S4, and S5, respectively, and headers corresponding thereto may bereferred to as H1, H2, H3, H4, and H5, respectively. The headers may beadded to the segments to generate respective link layer packets.

When an input IP packet is an IPv4 packet, packet type fields of H1 toH5 may have a value of 000. In addition, PC field values of H1 to H5 mayhave a segmented packet as a payload and thus may be 1.

An LI value of H1 to H4 does not have a last segment as a payload andthus may be 0. An LI value of H5 has a last segment as a payload andthus may be 1. Seg_ID, that is, a segment ID field of H1 to H5 hassegments from the same packet as a payload and thus may have the samevalue (000).

Seg_SN, that is, a segment sequence number field of H1 to H5 maysequentially represent H1 to H5 as 0000B to 0100B. A segment length IDfield of H1 to H4 may have a value of 0010 corresponding to an ID of a1024-byte length. A segment length field of H5 may have a value of010101111100 indicating 1404 bytes.

FIG. 66 is a diagram illustrating a method for using CRC encoding withrespect to a header of a link layer packet when an IP packet istransmitted to a link layer, according to another embodiment of thepresent invention.

When an IP packet is segmented and processed as a link layer packet, areceiver needs to receive a plurality of link layer packets to recombinean original IP packet. The receiver may need to check integrity of therecombined IP packet.

To this end, CRC encoding may be used. Prior to segmentation of an IPpacket, CRC may be added subsequent to the IP packet. When an IP packetto which CRC is added is segmented, a link layer packet including a lastsegment may also include CRC. The receiver may check the CRC anddetermine whether recombination is successful without error.

In general, the CRC may be added to a last part of a packet but may bepositioned at another position in some embodiments.

FIG. 67 is a diagram illustrating a configuration of a link layer packetwhen signaling information is transmitted to a link layer according toanother embodiment of the present invention.

In this case, a header of a link layer packet may include a fixed headerand an extended header. The fixed header may have a length of 1 byte andthe extended header may have a fixed length or a variable length. Alength of each header may be changed according to a designer'sintention.

The fixed header may include a packet type field, a PC field, and/or aconcatenation count field. According to another embodiment of thepresent invention, the fixed header may include a packet type field, aPC field, an LI field, and/or a segment ID field.

The extended header may include a signaling class field, an informationtype field, and/or a signaling format field. According to anotherembodiment of the present invention, the extended header may furtherinclude a payload length part. According to another embodiment of thepresent invention, the extended header may include a segment sequencenumber field, a segment length ID field, a signaling class field, aninformation type field, and/or a signaling format field. According toanother embodiment of the present invention, the extended header mayinclude a segment sequence number field and/or a segment length IDfield. According to another embodiment of the present invention, theextended header may include a segment sequence number field and/or alast segment length field.

The fields of the fixed header will now be described.

As described above, the packet type field may indicate a type of apacket input to a link layer. When signaling information is input to alink layer, a value of the packet type field may be 110B.

The PC field, the LI field, the segment ID field, the segment sequencenumber field, the segment length ID field, and the last segment lengthfield are the same as the aforementioned fields. The concatenation countfield may be the same as the aforementioned count field.

The fields of the extended header will now be described.

When the PC field has a value of 0, the extended header may include asignaling class field, an information type field, and/or a signalingformat field. In addition, according to a value of the signaling formatfield, the extended header may further include a payload length part.

The signaling class field may indicate a type of signaling informationincluded in a link layer packet. The signaling information indicated bythe signaling class field may be, for example, fast information channel(FIC) information or header compression information. The signalinginformation indicated by the signaling class field will be describedlater.

The information type field may indicate detailed information thereofwith respect to signaling information of a type indicated by thesignaling class field. The information type field may be separatelydefined according to a value of the signaling class field.

The signaling format field may indicate a format of signalinginformation included in a link layer packet. The format indicated by thesignaling format field may be a section table, a descriptor, XML, or thelike. The format indicated by the signaling format field will bedescribed later.

The payload length part may indicate a length of signaling informationincluded in a payload of a link layer packet. The payload length partmay be a combination of length fields indicating lengths of concatenatedsingling information items. Each length field may have a size of 2 bytesbut the size may be changed according to a system configuration. A totallength of the payload length part may be represented by the sum oflengths of the length fields. In some embodiments, a padding bit foralignment of bytes may be added. In this case, the total length of thepayload length part may be increased by as much as the padding bit.

Whether the payload length part exists may be determined according to avalue of the signaling format field. Like the section table and thedescriptor, when corresponding signaling information has a value of alength of the corresponding signaling information, a separate lengthfield may not be required. However, signaling information that does nothave a separate length value may require a separate length field. In thecase of signaling information that does not have a separate lengthvalue, a payload length part may exist. In this case, the payload lengthpart may include length fields, the number of which corresponds to thenumber of count fields.

When the PC field has a value of 1 and the LI field has a value of 1,the extended header may include a segment sequence number field and/or alast segment length field. When the PC field has a value of 1 and the LIfield has a value of 0, the extended header may include a segmentsequence number field and/or a segment length ID field.

The segment sequence number field, the last segment length field, andthe segment length ID field are the same as the aforementioned fields.

When the PC field has a value of 1 and the LI field has a value of 0, ifa payload of a corresponding link layer packet is a first segment, theextended header may further include additional information. Theadditional information may include a signaling class field, aninformation type field, and/or a signaling format field. The signalingclass field, the information type field, and the signaling format fieldare the same as the aforementioned fields.

FIG. 68 is a diagram illustrating meaning of values indicated by fieldswith respect to a configuration of a link layer packet when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

As described above, a type of signaling information included in a linklayer packet may be represented by a signaling class field (t68010).

For example, when a value of the signaling class field is 000, signalinginformation may be signaling information for a fast information channel(FIC). When a value of the signaling class field is 001, the signalinginformation may be signaling information for emergency alert. When avalue of the signaling class field is 010, the signaling information maybe signaling information for header compression. When a value of thesignaling class field is 011 to 110, the signaling class field may bereserved for a singling information type for future use. When a value ofthe signaling class field is 111, various types of signaling informationmay be included in the link layer packet.

A signaling information value indicated by the signaling class field maybe differently determined in some embodiments.

As described above, a format of signaling information included in thelink layer packet may be indicated by the signaling format field(t68020).

For example, when a value of the signaling format field is 00, thesignaling information may be included in a payload in the form of asection table. When a value of the signaling format field is 01, thesignaling information may be included in a payload in the form of adescriptor. When a value of the signaling format field is 10, thesignaling information may be included in a payload in the form of XML.When the signaling format field has a value of 11, the signalinginformation may be included in a payload in other forms.

A format indicated by the signaling format field may be differentlydetermined in some embodiments.

FIG. 69 is a diagram illustrating a configuration of a link layer packetwhen signaling information is one section table with respect to theconfiguration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

According to the present embodiment, it is assumed that one sectiontable is encapsulated as one link layer packet.

According to the present embodiment, a header of a link layer packet mayinclude a packet type field with a value of 110. Since one signalinginformation item is included in a payload of a link layer packet, the PCfield may have a value of 0 and a concatenation count field may have avalue of 0000. The signaling class field and the information type fieldmay have a value according to data contained in the correspondingsection table. Since signaling information is a section table, thesignaling format field may have a value of 00.

According to the present embodiment, an input section table may bepositioned in a payload of a link layer packet without change.

According to the present embodiment, in order to use a length of a linklayer packet, information of a section table may be used. As describedabove, a section table may include a field indicating a length of thecorresponding section table. The field may be referred to as a lengthfield. The length field may be positioned at a fixed position in thesection table. Since one section table is input to a payload of a linklayer without change, a length field thereof may be positioned at aposition spaced apart from a start point of the payload of the linklayer packet by a predetermined offset. Accordingly, a total payloadlength of a link layer may be known using the length field. In the caseof a section table, a length field of 12 bits may be positioned at aposition spaced apart from the start point of the payload by 12 bits.The length field may be referred to as a Section_length field.

An Lsection of a length field may indicate a length to a last part of asection table immediately after the length field. Accordingly, 3 bytesof the remaining part of the section table and 2 bytes of a headerlength of a link layer packet may be added to obtain a total length ofthe link layer packet. That is, a total length Lt of the link layerpacket may be (Lsection+5) bytes.

Upon receiving a link layer packet according to the present embodiment,a receiver may process corresponding signaling information (sectiontable) using the signaling class field and/or the information typefield, etc. In addition, the receiver may check a value of a table ID (8bits) of the section table and process the corresponding signalinginformation.

FIG. 70 is a diagram illustrating a configuration of a link layer packetwhen signaling information is one descriptor with respect to theconfiguration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

According to the present embodiment, it is assumed that one descriptoris encapsulated as one link layer packet.

According to the present embodiment, header information of the linklayer packet may correspond to encapsulation of one section table.However, the signaling class field and the information type field mayhave a value according to data contained in the correspondingdescriptor. In addition, since signaling information is a descriptor,the signaling format field may have a value of 01.

According to the present embodiment, an input descriptor may bepositioned in a payload of a link layer packet without change.

According to the present embodiment, in order to check a length of alink layer packet, information of a descriptor may be used. This may besimilar to encapsulation of the aforementioned one section table.However, a position of a field indicating a length of a correspondingdescriptor may be changed in the descriptor. In the case of adescriptor, a length field may be positioned at a position spaced apartfrom a start point of a payload by 8 bits and may have a length of 8bits. Based thereon, a total length of the link layer packet may beknown.

Upon receiving a link layer packet according to the present embodiment,a receiver may process signaling information (descriptor) using thesignaling class field and/or the information type field, etc. Inaddition, the receiver may check a descriptor tag (8 bits) of adescriptor and process corresponding signaling information.

FIG. 71 is a diagram illustrating a configuration of a link layer packetwhen signaling information is a plurality of descriptors with respect tothe configuration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

According to the present embodiment, a plurality of descriptors may beconcatenated and encapsulated in a payload of a link layer packet.

A header of a link layer packet according to the present embodiment mayinclude a packet type field of a value of 110 and a PC field of a valueof 0. The concatenation count field may indicate the number ofconcatenated descriptors. The signaling class field and the informationtype field may have a value according to data of a correspondingdescriptor. Since signaling information is a descriptor, the signalingformat field may have a value of 01.

A total length of a link layer packet according to the presentembodiment may be calculated using a similar method to concatenation ofIP packets. A value of a descriptor_length field of a descriptor may besequentially read by as much as the number indicated by the count fieldfrom a start point of a payload. The read values may be summed to obtaina total length of a payload of a link layer packet. Here, a headerlength of a link layer packet may be added to the resulting value toobtain a total length of a link layer packet.

FIG. 72 is a diagram illustrating a configuration of a link layer packetwhen signaling information is a plurality of section tables with respectto the configuration of the link layer packet when signaling informationis transmitted to a link layer, according to another embodiment of thepresent invention.

According to the present embodiment, a plurality of section tables maybe concatenated and encapsulated in a payload of a link layer packet.

A header of a link layer packet according to the present embodiment mayinclude a packet type field with a value of 110, a PC field with a valueof 0, and a concatenation count field indicating the number ofconcatenated section tables. The signaling class field and theinformation type field may have a value according to data ofcorresponding section tables. Since signaling information is a sectiontable, the signaling format field may have a value of 00.

A total length of a link layer packet according to the presentembodiment may be obtained similarly to the case in which theaforementioned descriptors are concatenated. As described above, alength field of 12 bits may be positioned at a position spaced apartfrom a start point of the section table by 12 bits in a section table. Alength of the remaining section table may be added to the length fieldto obtain a total length of a section table. Total lengths of sectiontables may be summed to obtain a total length of concatenated sectiontables, that is, a length of a link layer packet. Here, a header lengthof a link layer packet may be added to the resulting value to obtain atotal length of the link layer packet.

FIG. 73 is a diagram illustrating a configuration of a link layer packetwhen signaling information does not have a separate length value withrespect to the configuration of the link layer packet when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

According to the present embodiment, the aforementioned signaling formatfield may indicate that corresponding signaling information is signalinginformation that does not have XML or a separate length value. Asdescribed above, an extended header may further include a payload lengthpart.

According to the present embodiment, a header may include a packet fieldwith a value of 110, a PC field with a value of 0, and a concatenationcount field indicating the number of concatenated signaling informationitems. The subsequent signaling class field and information type fieldmay have values according to data of the corresponding signalinginformation. Since the signaling information is XML or separatesignaling information, the signaling format field may have a value of 10or 11.

As described above, an added payload length part may include a pluralityof length fields. Each length field may indicate a length of eachsignaling information item. Accordingly, length fields, the number ofwhich corresponds to the number indicated by the concatenation countfield, may exist. The length field may have a length of 2 bytes. Alength of the length field may be changed according to a systemconfiguration. A padding bit for byte alignment may be further added toa link layer packet.

According to the present embodiment, in order to obtain a total lengthof a link layer packet, length fields may be used (t73010). When a valueindicated by the concatenation count field is n, a payload length partof a total of 2*n bytes may be added to a header. In addition, whenvalues of length fields indicating lengths of concatenated signalinginformation items S1, S2, Sn are L1, L2, . . . , Ln, if a header lengthof a link layer packet is 2 bytes, a total length LT of a link layerpacket may be represented as illustrated (t73010).

FIG. 74 is a diagram illustrating a configuration of a link layer packetwhen one signaling information item is segmented into a plurality ofsegments with respect to the configuration of the link layer packet whensignaling information is transmitted to a link layer, according toanother embodiment of the present invention.

When input signaling information exceeds a processing range of aphysical layer, one signaling information item may be segmented into aplurality of segments. Each segmented segment may be encapsulated in apayload of each link layer packet.

The configuration according to the present embodiment may have a similarheader configuration to the case in which the aforementioned IP packetis segmented. The packet type field may have a value of 110 whensignaling information is input. The PC field, the LI field, the segmentID field, the segment sequence number field, the segment length IDfield, and the last segment length field may be the same as in theaforementioned case in which an IP packet is segmented.

According to the present embodiment, unlike in the aforementioned casein which the IP packet is segmented, a first packet may further includeadditional information (t74010). As described above, the additionalinformation may include a signaling class field, an information typefield, and/or a signaling format field. When a receiver receives allsegments, the additional information items may facilitate processing ofthe corresponding signaling information.

Information about an extended header of a link layer packet may be knownaccording to a combination of an LI field value of a segment sequencenumber field. When a value of the LI field is 0 and a value of a segmentsequence number field is 0000 (i.e., in the case of a first segment), alength of the extended header may be 2 bytes. When a value of the LIfield is 0 and a value of the segment sequence number field is not 0000,a length of the extended header may be 1 byte. When a value of the LIfield is 1, a length of the extended header may be 2 bytes.

A total length of a link layer packet may be obtained by adding a lengthof a header of a link layer packet to the length of the segment,calculated through the segment length ID field or the last segmentlength field.

Like in the case in which an IP packet is segmented, CRC encoding mayalso be used when signaling information is segmented. The CRC may beadded to a last part of the signaling information. The CRC may be usedto check integrity of recombination when a receiver recombines signalinginformation. When signaling information to which the CRC is added issegmented, a link layer packet including a last segment may also includeCRC.

In general, CRC may be added to a last part of a packet or may bepositioned at other positions in some embodiments.

FIG. 75 is a diagram illustrating a method for transmitting a broadcastsignal according to an embodiment of the present invention.

According to an embodiment of the present invention, the method fortransmitting the broadcast signal may include generating a plurality ofsignaling information items for signaling broadcast data (t75010),generating a link layer packet using the signaling information items(t75020), generating a broadcast signal using the link layer packet(t75030), and/or transmitting the broadcast signal (t75040).

First, a plurality of signaling information items may be generated(t75010). Here, the signaling information items may be used to signalother broadcast data transmitted through a link layer. The content andtype of signaling information may be changed in some embodiments. Thegenerating of the signaling information items may be performed by afirst module to be described later.

A link layer packet may be generated using the generated signalinginformation items (t75020). This step may correspond to a procedure forgenerating a link layer packet by concatenating the aforementionedsignaling information items. As described above, the link layer packetmay include a link layer header and a link layer payload. The link layerheader may include a packet type field, a packet configuration field,and a count field, and the packet type field may indicate thatinformation included in a link layer payload is signaling information.The packet configuration field may indicate whether a link layer payloadincludes a plurality of signaling information items and the count fieldmay indicate the number of the signaling information items included inthe link layer payload. Since the signaling information items areconcatenated, a plurality of signaling information items may beconcatenated and included in a link layer payload.

Here, the link layer header may refer to the aforementioned fixed headeror extended header or an entire header including the fixed header andthe extended header according to the context. The packet configurationfield may refer to the aforementioned PC field. The link layer payloadmay refer to a payload of a link layer packet. The generating of thelink layer packet may be performed by a second module to be describedlater.

A broadcast signal may be generated using the generated link layerpacket (t75030). In a physical layer, predetermined encoding,modulation, etc. may be applied to the link layer packet generated in alink layer. Through the link layer packet, the physical layer mayperform physical layer processing irrespective of a type of inputpacket/input signaling information. A broadcast signal may be generatedthrough the predetermined physical layer processing. The generating ofthe broadcast signal may be performed by a third module to be describedlater.

The broadcast signal may be transmitted to a receiver through thereceiver (t75040). The broadcast signal may be transmitted through abroadcast network and a transmission method may be changed in someembodiments. The method for transmitting the broadcast signal may beperformed by a third module to be described later.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a link layer header may furtherinclude a signaling class field, an information type field, and asignaling format field. The signaling class field may indicate asignaling target of signaling information, the information type fieldmay include data about the signaling information, and the signalingformat field may indicate a format of signaling information. Thesignaling class field, the information type field, and the signalingformat field may be the same as the aforementioned fields.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a signaling format field mayindicate that a plurality of signaling information items including alink layer payload is a plurality of section tables. This may mean thata format of signaling information indicated by signaling format field isa section table.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a length of a link layer headermay be determined according to a value of a signaling format field. Thatis, as described above, this is because whether a link layer headerfurther includes an additional payload length part is determinedaccording to a value of the signaling format field. In addition, alength of a link layer payload may be determined according to values ofsection_length_fields of a plurality of section tables. As describedabove, section_length_fields may exist in a fixed position in a sectiontable. A length of the link layer payload may be calculated based on thesum of values of the section_length_fields.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, section_length_fields of aplurality of section tables may be sequentially positioned on a linklayer payload. As described above, when section tables are concatenated,section_length_fields may be arranged with an interval in a link layerpayload. The length fields may be positioned at a position fixed from astart point of each section table. Lengths of the respective sectiontables may be different, and thus distance between the length fields maybe different. As described above, the section_length_field may indicatea length of a corresponding section table.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a signaling format field mayindicate that a plurality of signaling information items including alink layer payload are a plurality of descriptors. This may be a case inwhich a plurality of descriptors may be concatenated to configure apayload, and as described above, may be indicated by the signalingformat field.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a link layer header may furtherinclude a payload length part including a plurality of payload lengthfields. The payload length fields may refer to length fields of theaforementioned payload length part. As described above, the respectivepayload length fields may indicate a plurality of signaling informationitems. This may correspond to the case in which signaling informationincluded in the link layer packet has no separate length field.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, whether a link layer headerfurther includes a payload length part may be determined according to avalue of the signaling format field. When the signaling informationincluded in the link layer packet has no separate length field, a valueof the signaling format field may correspond to 1×. Accordingly, whethera payload length part exists may be recognized through a value of thesignaling format field.

According to another embodiment of the present invention, the method fortransmitting the broadcast signal may be a method in which theaforementioned segmentation is performed. In this case, the method fortransmitting the broadcast signal may include generating signalinginformation for signaling broadcast data, generating a link layer packetusing the signaling information, generating a broadcast signal using thelink layer packet, and/or transmitting the broadcast signal. Therespective steps may be performed by a first module, a second module,and a third module in the stated order.

In the method for transmitting the broadcast signal, a link layer packetmay include a link layer header and a link layer payload, and the linklayer payload may include one of segmented segments. The link layerheader may include a packet type field and a packet configuration field,and the packet type field may indicate that information including a linklayer payload is signaling information. The packet configuration fieldmay indicate whether a link layer payload includes one of segmentssegmented from signaling information.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, when a segment included in a linklayer payload is a first segment among segmented segments, a link layerheader may include a signaling class field, an information type field,and a signaling format field. The signaling class field may indicate asignaling target, the information type field may include data aboutsignaling information, and the signaling format field may indicate aformat of signaling information. The signaling class field, theinformation type field, and the signaling format field may be the sameas the aforementioned fields.

The aforementioned steps may be omitted or substituted with other stepsfor performing the similar/same operation in some embodiments.

FIG. 76 is a diagram illustrating an apparatus for transmitting abroadcast signal according to an embodiment of the present invention.

The apparatus for transmitting a broadcast signal according to anembodiment of the present invention may include a first module t76010, asecond module t76020, and/or a third module t76030.

The first module t76010 may generate a plurality of signalinginformation items. The first module may perform a procedurecorresponding to a step for generating a plurality of signalinginformation items. In addition, when segmentation is performed, thefirst module may perform a procedure corresponding to a step forgenerating signaling information for signaling the aforementionedbroadcast data in some embodiments.

The second module t76020 may generate a link layer packet using thegenerated signaling information items. The second module may perform aprocedure corresponding to a step for generating a link layer packetusing the aforementioned signaling information items. In addition, whensegmentation is performed, the second module may perform a procedurecorresponding to a step for generating a link layer packet using theaforementioned signaling information.

The third module t76030 may generate a broadcast signal using thegenerated link layer packet. In addition, the third module may transmitthe generated broadcast signal. The third module may perform operationscorresponding to a step for generating a broadcast signal using theaforementioned link layer packet and a step for transmitting a broadcastsignal. In addition, when segmentation is performed, the third modulemay perform an operation corresponding to a step for generating abroadcast signal using the aforementioned link layer packet and a stepfor transmitting the broadcast signal in some embodiments.

The aforementioned first module, second module, and third module may beprocessors for executing consecutively performed procedures stored in amemory (or a storage unit). In addition, the aforementioned firstmodule, second module, and third module may be hardware elementspositioned in/outside the apparatus.

The aforementioned modules may be omitted or substituted with othersteps for performing the similar/same operation in some embodiments.

A module or a unit may be processors for executing consecutivelyperformed procedures stored in a memory (or a storage unit). Inaddition, the steps according to the aforementioned embodiments of thepresent invention may be performed by hardware/processors. Eachmodule/block/unit according to the aforementioned embodiments of thepresent invention may function as hardware/processors. In addition, themethods proposed by the present invention may be implemented as code.The code can be written in a storage medium readable by a processor andthus can be read by a processor provided by an apparatus.

For convenience of description, the drawings are separately describedbut a new embodiment may be designed by combining embodimentsillustrated in the drawings. In addition, according to necessity ofthose skilled in the art, design of a computer readable recording mediumwith a program recorded therein for executing the aforementionedembodiments is within the scope of the invention.

As described above, an apparatus and a method according to the presentembodiment may be configured by selectively combining all or some of theaforementioned embodiments for various modifications rather than beingrestrictively limited.

Meanwhile, the apparatus and method proposed by the present inventionmay be embodied as code readable by a processor in a recording mediumreadable by a processor included in a network device. The recordingmedium readable by the processor may include any type of recordingapparatus in which data readable by a processor is stored. Examples ofthe recording medium readable by the processor may include a ROM, a RAM,a CD-ROM, a magnetic tape, a floppy disk, and an optical data storagedevice and embodied in the form of a carrier wave for transmissionthrough the Internet. The processor readable recording medium can alsobe distributed over network coupled computer systems so that thecomputer readable code is stored and executed in a distributed fashion.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims and themodifications may not be separately understood from the spirit and scopeof the present invention.

In addition, in the specification, the present invention has beendescribed in terms of an apparatus and a method, and as necessary, theapparatus and the method may be supplementarily applied.

MODE FOR INVENTION

Various embodiments have been described in Best Mode for implementingthe present invention.

INDUSTRIAL APPLICABILITY

The present invention has industrial applicability in a predeterminedindustrial field associated with a method for transmitting a broadcastsignal, a method for receiving a broadcast signal, an apparatus fortransmitting a broadcast signal, and an apparatus for receiving abroadcast signal.

The invention claimed is:
 1. A method for transmitting a broadcastsignal, the method comprising: generating a link layer packet, whereinthe link layer packet includes a header and a payload, wherein theheader includes a packet type field, and the packet type fieldrepresents a type of input data before encapsulation into the link layerpacket, wherein in response to the packet type field represents that theinput data relates to a Movie Picture Experts Group-2 (MPEG-2) TransportStream (TS) packet, the header included in the link layer packet furtherincludes a deleted null packet indicator for representing the number ofdeleted null TS packets prior to the link layer packet, wherein inresponse to the packet type field represents that the input data relatesto an Internet Protocol (IP) packet, the header further includes payloadconfiguration information, and the payload configuration informationalways immediately follows the packet type field within a fixed headerwhile at least one field immediately following the payload configurationinformation within the fixed header changes based on the payloadconfiguration information, wherein a size of an additional headerincluded in the link layer packet as well as a field included in theadditional header are determined based on the payload configurationinformation within the fixed header, further the size of the additionalheader is limited to zero (0) byte, 1 byte or values more than the 1byte based on the payload configuration information, wherein in responseto the packet type field represents that the input data relates to theIP packet and a configuration indicating field included in the headerrepresents that the payload carries a segment of one input packet, theheader included in the link layer packet further includes segmentsequence number for representing an order of a corresponding segmentcarried by the link layer packet, wherein in response to the packet typefield represents that the input data relates to the IP packet and theconfiguration indicating field included in the header represents thatthe payload carries concatenated input packets, the header included inthe link layer packet further includes count information forrepresenting the number of the concatenated input packets included inthe link layer packet, and wherein the packet type field is furtherconfigured to identify whether the IP packet corresponds to IPv4 packetor compressed IP packet, and further an IP header compression scheme isprovided to the IPv4 packet; generating the broadcast signal based onthe link layer packet; and transmitting the broadcast signal.
 2. Anapparatus for transmitting a broadcast signal, the apparatus comprising:a processor configured to generate a link layer packet, wherein the linklayer packet includes a header and a payload, wherein the headerincludes a packet type field, and the packet type field represents atype of input data before encapsulation into the link layer packet,wherein in response to the packet type field represents that the inputdata relates to a Movie Picture Experts Group-2 (MPEG-2) TransportStream (TS) packet, the header included in the link layer packet furtherincludes a deleted null packet indicator for representing the number ofdeleted null TS packets prior to the link layer packet, wherein inresponse to the packet type field represents that the input data relatesto an Internet Protocol (IP) packet, the header further includes payloadconfiguration information, and the payload configuration informationalways immediately follows the packet type field within a fixed headerwhile at least one field immediately following the payload configurationinformation within the fixed header changes based on the payloadconfiguration information, wherein a size of an additional headerincluded in the link layer packet as well as a field included in theadditional header are determined based on the payload configurationinformation within the fixed header, further the size of the additionalheader is limited to zero (0) byte, 1 byte or values more than the 1byte based on the payload configuration information, wherein in responseto the packet type field represents that the input data relates to theIP packet and a configuration indicating field included in the headerrepresents that the payload carries a segment of one input packet, theheader included in the link layer packet further includes segmentsequence number for representing an order of a corresponding segmentcarried by the link layer packet, wherein in response to the packet typefield represents that the input data relates to the IP packet and theconfiguration indicating field included in the header represents thatthe payload carries concatenated input packets, the header included inthe link layer packet further includes count information forrepresenting the number of the concatenated input packets included inthe link layer packet, wherein the packet type field is furtherconfigured to identify whether the IP packet corresponds to IPv4 packetor compressed IP packet, and further an IP header compression scheme isprovided to the IPv4 packet, and wherein the processor is furtherconfigured to generate the broadcast signal based on the link layerpacket; and a transmitter configured to transmit the broadcast signal.3. A method for receiving a broadcast signal, the method comprising:receiving the broadcast signal, wherein the broadcast signal includes alink layer packet, wherein the link layer packet includes a header and apayload, wherein the header includes a packet type field, and the packettype field represents a type of input data before encapsulation into thelink layer packet, wherein in response to the packet type fieldrepresents that the input data relates to a Movie Picture ExpertsGroup-2 (MPEG-2) Transport Stream (TS) packet, the header included inthe link layer packet further includes a deleted null packet indicatorfor representing the number of deleted null TS packets prior to the linklayer packet, wherein in response to the packet type field representsthat the input data relates to an Internet Protocol (IP) packet, theheader further includes payload configuration information, and thepayload configuration information always immediately follows the packettype field within a fixed header while at least one field immediatelyfollowing the payload configuration information within the fixed headerchanges based on the payload configuration information, wherein a sizeof an additional header included in the link layer packet as well as afield included in the additional header are determined based on thepayload configuration information within the fixed header, further thesize of the additional header is limited to zero (0) byte, 1 byte orvalues more than the 1 byte based on the payload configurationinformation, wherein in response to the packet type field representsthat the input data relates to the IP packet and a configurationindicating field included in the header represents that the payloadcarries a segment of one input packet, the header included in the linklayer packet further includes segment sequence number for representingan order of a corresponding segment carried by the link layer packet,wherein in response to the packet type field represents that the inputdata relates to the IP packet and the configuration indicating fieldincluded in the header represents that the payload carries concatenatedinput packets, the header included in the link layer packet furtherincludes count information for representing the number of theconcatenated input packets included in the link layer packet, andwherein the packet type field is further configured to identify whetherthe IP packet corresponds to IPv4 packet or compressed IP packet, andfurther an IP header compression scheme is provided to the IPv4 packet;and obtaining the input data based on the link layer packet.
 4. Anapparatus for receiving a broadcast signal, the apparatus comprising: areceiver configured to receive the broadcast signal, wherein thebroadcast signal includes a link layer packet, wherein the link packetincludes a header and a payload, wherein the header includes a packettype field, and the packet type field represents a type of input databefore encapsulation into the link layer packet, wherein in response tothe packet type field represents that the input data relates to aMovie-Picture Experts Group-2 (MPEG-2) Transport Stream (TS) packet, theheader included in the link layer packet further includes a deleted nullpacket indicator for representing the number of deleted null TS packetsprior to the link layer packet, wherein in response to the packet typefield represents that the input data relates to an Internet Protocol(IP) packet, the header further includes payload configurationinformation, and the payload configuration information alwaysimmediately follows the packet type field within a fixed header while atleast one field immediately following the payload configurationinformation within the fixed header changes based on the payloadconfiguration information, wherein a size of an additional headerincluded in the link layer packet as well as a field included in theadditional header are determined based on the payload configurationinformation within the fixed header, further the size of the additionalheader is limited to zero (0) byte, 1 byte or values more than the 1byte based on the payload configuration information, wherein in responseto the packet type field represents that the input data relates to theIP packet and a configuration indicating field included in the headerrepresents that the payload carries a segment of one input packet, theheader included in the link layer packet further includes segmentsequence number for representing an order of a corresponding segmentcarried by the link layer packet, wherein in response to the packet typefield represents that the input data relates to the IP packet and theconfiguration indicating field included in the header represents thatthe payload carries concatenated input packets, the header included inthe link layer packet further includes count information forrepresenting the number of the concatenated input packets included inthe link layer packet, and wherein the packet type field is furtherconfigured to identify whether the IP packet corresponds to IPv4 packetor compressed IP packet, and further an IP header compression scheme isprovided to the IPv4 packet; and a processor configured to obtain theinput data based on the link layer packet.
 5. The method according toclaim 1, wherein in response to a first information table is included inthe payload as the link layer signaling data, the first informationtable provides information on mapping relation between Physical LayerPipes and data components related with a broadcast service.
 6. Theapparatus according to claim 2, wherein in response to a firstinformation table is included in the payload as the link layer signalingdata, the first information table provides information on mappingrelation between Physical Layer Pipes and data components related with abroadcast service.